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Monitoring and maintaining the TC system

You perform some maintenance tasks in response to conditions discovered during system monitoring. You can also change certain settings as needed to meet changing operational requirements.

Monitoring pair status and license capacity

You should monitor the TrueCopy system frequently to keep track of and maintain the copy pairs.

The following are a couple of examples of when you would check the status of a pair:

  • Check the status before performing a pair operation. Each operation requires a specific status or set of statuses.
  • Check status to see that pairs are operating correctly and that data is updated from P-VOLs to S-VOLs in PAIR status, or that differential data management is performed in Split status. Pair status changes when an operation is performed.

You can check the TC pair status by HDvM - SN or CCI. Monitoring should be repeated frequently. Email notifications of problems can be set up using HDvM - SN or Maintenance Utility.

To perform this task in CCI, use the pairdisplay command or the pairevtwait command.

Procedure

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. In the Storage Systems tree, click Replication Remote Replication.

  3. In the Remote Replication window, click the TC Pairs tab, and then locate the pair volume with the status you want to review.

  4. In the TC Pairs tab, click More Actions View Pair Properties and review Status.

    For more information, see Pair status definitions .

Next steps

To monitor license capacity, see the Summary area in the Replication window.

Pair status definitions

Both Device Manager - Storage Navigator and CCI pair status names appear in the Status column, except when the names are the same. When they are the same, the CCI status does not appear.

The following table shows both types of status names and their descriptions. In some cases, a particular status has no exact parallel status in the other interface. This is noted.

When checking the pair status, click Refresh to display the latest information. The P-VOL access and S-VOL access columns in the following table indicate whether the volumes accept read/write.

HDvM - SN status

CCI status

Description

P-VOL access

S-VOL access

Unpaired in HDvM - SN

SMPL

This volume is not currently assigned to a TrueCopy pair.

Read/Write

Read/Write

GUID-C86DE477-F52E-464E-B0E1-0DEA5EB304F1-low.png COPY*

COPY

The initial copy operation for this pair is in progress. This pair is not yet synchronized.

Read/Write

Read Only

GUID-9A8B66E5-6ADF-426F-BDAC-94700AEAFA73-low.png PAIR

PAIR

  • The pair is synchronized
  • Updates from the host to the P-VOL are duplicated in the S-VOL.

Read/Write

Read Only

GUID-DA3C1DD1-2B44-4163-BACB-D478AD15B047-low.png PSUS

(pair suspended-split)

SSUS, PSUS

  • The pair was split by a user or deleted from the secondary system.
  • The pair is not synchronized.
  • When you split the pair in the primary system, that system changes the status of the P-VOL and S-VOL to this status.
  • In this status, updates to the S-VOL stop. The storage system keeps track of updates to the P-VOL in order to update the S-VOL when the pair is resynchronized.

    CCI also shows the P-VOL in this status.

  • When you split the pair in the secondary system, that system changes the status of the S-VOL to this status. The primary system detects this and changes the P-VOL to this status.

    CCI shows the S-VOL status as SSUS.

  • When you release the pair in the secondary system, that system changes the S-VOL status to SMPL . The primary system detects this and changes the P-VOL to this status. The pair must be released from the primary system in order to change P-VOL status to SMPL.
  • CCI PSUS status indicates that although the paired status is retained, the user split the pair. This status is only for the P-VOL. While the pair is split, the storage system keeps track of updates to the P-VOL in the differential bitmaps.

Read/Write

Read only if Secondary Volume Write option is disabled.

Read/Write if Secondary Volume Write option is enabled.

GUID-07E8EF44-0427-47F8-BC69-4BA0B40FE866-low.pngPSUE

(pair suspended-error)

PSUE

  • The primary or secondary system splits the pair due to an error.
  • If the primary system cannot keep the pair synchronized for any reason, it changes the status of the P-VOL and S-VOL (if possible) to this status.
  • The pair is not synchronized.
  • CCI PSUE indicates that although the paired status is retained, updates to the S-VOL is sopped due to an error status. CCI PSUE is PSUS (SSUS) caused by an internal error.
  • (VSP Gx00 models, VSP Fx00 models, and VSP E series) A user deleted the pair from the secondary system.
  • (VSP Gx00 models, VSP Fx00 models, and VSP E series) An error occurred in the secondary system or the secondary volume, or during an update copy of TrueCopy.
  • (VSP Gx00 models, VSP Fx00 models, and VSP E series) Communication with the secondary system was disabled.

Read/Write.

Read only if Primary Volume Fence Level is Data.

Read Only

- SSWS
  • CCI SSWS status indicates that the pair status is retained. The P-VOL and the S-VOL of the pair is switched and then they are resynchronized (horctakeover).

* When the pair status is COPY, neither cache nor shared memory can be added to or removed from the storage system. When either of these tasks is to be performed, wait until the pair status changes to PAIR, or split the TC pair, and then resynchronize when the cache or shared memory operation is completed.

Monitoring TC pair synchronization rate

You can check on the percentage of synchronized data between the P-VOL and S-VOL.

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. In the Storage Systems tree, click Replication Remote Replication.

  3. In the Remote Replication window, click the TC Pairs tab, and then select the pair whose rate you want to display.

  4. In the TC Pairs tab, click More Actions View Pair Synchronization Rate. Click Refresh to display the latest synchronization rate.

Monitoring TC operations history

In HDvM - SN, you can review the history of operations for a pair, including the operation's description, date and time it took place, primary and secondary system information, and other details.

Procedure

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. In the Storage Systems tree, click Replication.

  3. In the Replication window, click View History Remote Replication.

  4. In the History window, for Copy Type, select TC. The Description column displays operations, which are explained below.

Results

Note the following when viewing histories:
  • Operation rows might not appear in descending, chronological order.
  • The most recent operations are displayed up to a maximum of 524,288 (VSP 5000 series) or 8,192 (SVP E series), within the last seven days. If the history information of more than the maximum operations is generated within seven days, the excess information will be deleted in the order from oldest to newest. In addition, whenever the date changes, the information on the oldest date is deleted from the stored information, and the information older than seven days is not shown.
  • "LDEV ID" indicates the physical LDEV ID, even when you use CCI and use pair volumes in a virtual storage machine.
  • If a failed split occurred with two or more LDEVs at the same time, the number of pairs showing Pair Suspend (Failure) might not match the actual number of pairs in which the failure occurred.
  • If you use 1,000 or more pairs concurrently, some operation history might not be recorded.
  • You can use audit logs to check the history of TC pair operations. For details, see the Command Control Interface Command Reference.

Operations listed in the History window

The following table describes the operations listed in the History window.

Operation displayed

Description

Pair Add Start

Creation of the pair started.

Pair Add Complete

Creation of the pair completed.

Pair Delete

The pair was deleted.

Pair Suspend (Operation)

The pair was split.

Pair Suspend (Failure)

The pair was split (suspended) because of a failure.

Pair Resync. start

Resynchronization of the pair was started.

Pair Resync. Complete

Resynchronization of the pair was completed.

Changing P-VOL fence level

You can change the P-VOL's fence level, which specifies when to reject write operations to the P-VOL under certain failure circumstances.

For more information on fence levels, see Allowing I/O to the P-VOL after a split: Fence Level options.

Before you begin

  • Required status: Both volumes must be COPY or PAIR.
  • The Edit Pair Options window is used for the following procedure. If you select multiple pairs, the values do not display but are blank. When you change a value, the change applies to all selected pairs.

Procedure

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. In the Storage Systems tree, click Replication Remote Replication.

  3. In the Remote Replication window, click the TC Pairs tab then select the pair whose options are to be changed.

  4. In the TC Pairs tab, click More Actions Edit Pair Options.

  5. In the Edit Pair Options window, for Primary Volume Fence Level box, select the fence level for the pairs.

    • Never: The P-VOL can always be written to.
    • Data: The P-VOL cannot be written to.
    • Status: The P-VOL cannot be written to only if the primary system is not able to change S-VOL status to PSUE.
  6. Click Finish.

  7. In the Confirm window, review the settings and enter a task name in the Task Name box.

  8. Click Apply to save your settings in the system.

Forcibly deleting pairs

You forcibly delete a pair using HDvM - SN for the following reasons: A currently unpaired volume that was previously in a pair is unusable because previous pair information is still in the volume, or the pair cannot be connected to the remote storage system because of a communication error.

In the case of a communication error, delete the pair forcibly in both the local and the remote storage systems.

CautionThe following data is discarded when you forcibly delete pairs:
  • Data which is not sent to the secondary storage system when a pair in the primary storage system is deleted forcibly
  • Data which is not restored when a pair is deleted forcibly in the secondary storage system

In addition, if a pair is deleted forcibly when a journal contains a pair in the PAIR/COPY status, host I/Os to the pair might time out.

Before you begin

  • The volume must be unpaired.
  • Required role: Storage Administrator (System Resource Management)

Procedure

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. In the Storage Systems tree, click Logical Devices.

  3. Click the LDEVs tab, and then select the pair to be forcibly deleted.

  4. In the LDEVs tab, click More Actions Force Delete Pairs (TC Pairs).

  5. In the Force Delete Pairs (TC Pairs) window, ensure that the volume is in the Selected LDEVs table.

  6. In Task Name, enter the task name.

  7. Click Apply.

Saving pair information to a text file

In HDvM - SN, you can save pair status and other information to a tab-delimited TSV file.

Procedure

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. In the Storage Systems tree, click Replication Remote Replication.

  3. In the Remote Replication window, click More Actions Export.

  4. If necessary, follow instructions in online Help.

Monitoring copy operations and I/O statistical data

In HDvM - SN, you can monitor copy operations and I/O statistical data.

For details, see the Performance Guide.

Monitoring and maintaining remote connections and paths

You can access information about remote connections and paths to determine their status. This information is useful when you are diagnosing connectivity between the primary and secondary systems.

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. In the Storage Systems tree, click Replication Remote Connections.

  3. View connection properties and path information by clicking View Remote Connection Properties in the Remote Connections window.

  4. To check path and port information, from the Storage Systems tree, right- click the target storage system to select Remote Connections. Then click Connections (To) tab.

    Check connections under View Port Condition.Check Status and other details in the Connections (To) tab.

Remote path status definitions

You can understand the status of connections and paths better by knowing the definition of the status that you observe.

The following table provides remote path status descriptions.

Status

Definition

Normal

This path has been successfully established and can be used for TrueCopy remote copy activities.

Initialization Failed

The link initialization procedure with the secondary system has failed, because the physical path connection between either the primary and secondary system, or between the primary system and the host, was missing.

Communication Timeout

A timeout error has occurred between the primary and secondary system.

Path Rejected

The remote path link function has been rejected by the secondary system. All remote path resources in the secondary system might be used for other connections.

Serial Number Mismatch

The serial number of the control unit that is connected to this remote path does not match the serial number specified by the Add Remote Connection window.

Invalid Port Mode

The specified port does not have the initiator attribute.

RCU Port Number Mismatch

There are three possible causes:

  • The specified port in the secondary system is physically disconnected from the primary system.
  • The port is not configured as an RCU target port.
  • The specified port number is not available.

RCU Port Type Mismatch

The microcode on the remote side does not support the fibre remote copy function, or the specified port type is not RCU target.

Communication Failed

A timeout error has occurred on the path between the primary and secondary system.

Logical Blockade

This remote path was blockaded because a path error or a link error occurred continuously.

Program Error

This remote path was blockaded because a program error occurred.

In Progress

This remote path is in progress of changing the attribute of port.

Configuring additional remote paths

You can configure additional remote paths as needed. A maximum of eight remote paths are supported.

Before you begin

  • Review path-related prerequisites.
  • Required role: Storage Administrator (Remote Copy).

Procedure

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. In the Storage Systems tree, click Replication Remote Connections.

  3. In the Remote Connections window, click the Connections (To) tab.

  4. In the Connections (To) tab, select the remote connection where the remote path is to be added.

  5. In the Connections (To) tab, click More Actions Add Remote Paths.

  6. In the Add Remote Paths window, add a new remote path by selecting ports for the primary (left side) and secondary systems. You can make multiple selections. To add paths, click Add Path.

  7. In Select Type, select the port type.

  8. Select the port to use for the local storage system and the remote storage system. If you selected iSCSI for the port type, enter the IP address and the TCP port number for the port of the remote storage system. To add two or more paths, click Add Path.

  9. Click Finish.

  10. In the Confirm window, review the settings and enter a task name in the Task Name box.

  11. Click Apply to save your settings in the system.

Changing remote connection options

You can change remote connection options to optimize TrueCopy performance.

The following remote connection options affect how copy operations are performed:

  • Number of minimum paths for a pair. You can find detailed information in Minimum number of remote paths option
  • RIO MIH Time, which is the waiting time from when copy starts until when it ends. This value applies to the slots which received the request of copying data from the local storage system to the remote storage system.
  • Round trip time, which is the time limit for copying data to the S-VOL. For more information, see Round trip time option.

Before you begin

  • Required role: Storage Administrator (Remote Copy).

Procedure

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. In the Storage Systems tree, click Replication Remote Connections.

  3. Click the Connections (To) tab, and then select the remote connection whose options you want to change.

  4. In the Connections (To) tab, click Edit Remote Connection Options.

  5. In the Edit Remote Connection Options window, for Minimum Number of Paths, select the minimum number of paths between the secondary and primary system.

  6. For RIO MIH Time, enter an interval in seconds that, if exceeded, causes the data-transfer operation to be reported as failed by the system.

    The RIO MIH Time is the waiting time from when copy starts until when it ends. This value applies to the slots which received the request of copying data from the local storage system to the remote storage system. The range is 10-100 seconds, and the default is 15.
  7. For Round Trip Time, enter a time limit for data copy from P-VOL to S-VOL in ms. The range is 1-500 ms, and the default is 1.

  8. Click Finish.

  9. In the Confirm window, review the settings and enter a task name in the Task Name box.

  10. Click Apply to save your settings in the system.

Deleting remote paths

You can delete a remote path between a primary system and secondary system if you do not need that path.

Before you begin

  • Delete remote paths from the primary system.
  • Make sure that the remaining number of paths is equal to or greater than the minimum number of paths setting on the Add Remote Connection window, otherwise the delete path operation will fail.
  • Required role: Storage Administrator (Remote Copy).

Procedure

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. In the Storage Systems tree, click Replication Remote Connections.

  3. In the Remote Connections window, click the Connections (To) tab.

  4. In the Connections (To) tab, select the remote connection with the path to be deleted.

  5. Click More Actions Remove Remote Paths.

  6. In the Remove Remote Paths window, select the type of path to be removed (Fibre or iSCSI), and click Remove for each remote path to be removed. Note that remote paths become unselectable when the minimum number of paths is reached.

  7. Click Finish.

  8. In the Confirm window, review the settings and enter a task name in the Task Name box.

  9. Click Apply to save your settings in the system.

Deleting remote connections

You can delete the remote connection from the local storage system to a remote storage system.

When you delete a remote connection, the local storage system deletes all remote paths to the selected remote storage systems.

Deleting the TC relationship with a specific remote system does not affect TC operations between other local systems and the remote system.

After a remote system is deleted, you can reconfigure the remote path to then connect another remote system to the local system. You can also delete the remote connection and reconfigure the local system ports (bidirectional ports to ordinary target ports for fibre) to provide additional host channels for the local system.

Before you begin

  • All TC pairs must be deleted before removing the connection.
  • When the remote connection is deleted, all remote paths are deleted.
  • Required role: Storage Administrator (Remote Copy).

Procedure

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. In the Storage Systems tree, click Replication Remote Connections.

  3. In the Remote Connections window, click the Connections (To) tab.

  4. In the Connections (To) tab, select the remote connection to be deleted.

  5. Click More Actions Remove Remote Connections.

  6. In the Remove Remote Connections window, from the Selected Remote Connections table, select the connection to be removed.

    (You can review information about the connection by clicking Detail.)

  7. Click Apply.

Expansion of DP-VOL capacity while keeping pair status

You can expand the capacity of a DP-VOL used in the GAD, TrueCopy, Universal Replicator, ShadowImage, or Thin Image pair created between or on the following storage systems while keeping the pair status in each software product.

  • VSP 5000 series: Microcode version 90-04-04-00/00 or later
  • VSP G1x00, VSP F1500: Microcode version 80-06-82-xx/xx or later
  • VSP G/F350, G/F370, G/F700, G/F900: Microcode version 88-06-02-x0/00 or later
  • VSP E series: Microcode version 93-02-03-x0/00 or later

If only VSP G1x00, VSP F1500 is used and the expansion is only for a GAD pair, the supported microcode version is 80-06-74-xx/xx or later.

Expanding DP-VOL capacity used in TrueCopy pair

When deciding to expand the capacity of a DP-VOL used as a volume in a TC pair, understand that there are two different procedures, each depending on whether the TC pair shares the same volumes with other software or does not share the same volumes. This procedure describes expanding DP-VOL capacity when the TC pair does not share the volume (a TC pair alone).

Before you begin

Ensure that the following conditions are met:
  • A V-Vol to be expanded is not an external volume
  • The LDEV format is being performed on a V-Vol to be expanded
  • A pool containing a V-Vol to be expanded meets any of the following conditions:
    • Normal condition
    • The used capacity of the pool exceeds the depletion threshold
    • The pool is being shrunk
  • A V-Vol to be expanded is a volume created on the storage systems described in Expansion of DP-VOL capacity while keeping pair status
  • Make sure that there is enough TC license capacity for the page capacity assigned to the expanded volume capacity before the expansion
NoteOnly the assigned page capacity out of the DP-VOL capacity is counted as the TC license capacity.

Procedure

  1. Verify that both the P-VOL and S-VOL of a TC pair meet the prerequisites.

  2. Display the detailed information about the TC pair on CCI.

    Verify whether the current differential data management method is the Shared memory (SM) difference management or the hierarchical difference management by a drive. The DM column displayed by the pairdisplay command shows whether the shared memory (S) difference management is applied or the hierarchical (D) difference management is applied.
    # pairdisplay -g oradb -fe -fcx
    Group PairVol L/R Port# TID  LU  Seq# LDEV# P/S Status Fence    % P-LDEV# M CTG JID AP EM    E-Seq# E-LDEV# R/W QM DM P
    oradb dev1 L CL5-A-0 30 0 64568 301 P-VOL PAIR NEVER 100 303 - - - 1 - - - -/- - S N
    oradb dev1 R CL5-A-0 30 2 64568 303 S-VOL PAIR NEVER 100 301 - - - - - - - -/- - S N
    oradb dev2 L CL5-A-0 30 1 64568 302 P-VOL PAIR NEVER 100 304 - - - 1 - - - -/- - D N
    oradb dev2 R CL1-A-0 30 3 64568 304 S-VOL PAIR NEVER 100 302 - - - - - - - -/- - D N
    
    • If the SM difference management is applied, go to Step 3 to temporarily change to hierarchical difference management.
    • If the hierarchical difference management is applied, go to Step 4.
    • If using HDvM - SN, verify the advanced system settings No.5 and No.6.
      • If both the advanced system settings No.5 and No. 6 are set to Disable, the SM difference management is applied. Go to Step 3.
      • If either or both the advanced system settings No.5 and No.6 are set to Enable, the hierarchical difference management is applied. Go to Step 4.
  3. Change the differential data management method to the hierarchical difference management.

    1. Change system settings for hierarchical difference management.

      • If using CCI, set the system option mode (SOM) 1198 to ON and 1199 to OFF by using the raidcom modify system_opt command.

        Command example:

        raidcom modify system_opt -system_option_mode system -mode_id 1198 -mode enable
        raidcom modify system_opt -system_option_mode system -mode_id 1199 -mode disable
      • If using HDvM - SN, set the advanced system settings No. 5 to Enable and No.6 to Disable in the Edit Advanced System Settings window.
    2. Suspend the TC pair.

    3. Resynchronize the TC pair.

    4. Display the detailed information about the TC pair on CCI.

      Verify that the current differential data management method is the hierarchical difference management.
  4. Suspend the TC pair.

  5. Expand the S-VOL capacity in the TC pair.

    • If using CCI, add -request_id auto option to the raidcom extend ldev command to specify the asynchronous command processing.

      Command example

      The following command expands the capacity of LDEV#44:44 by 10 GB.

      raidcom extend ldev -ldev_id 0x4444 -capacity 10G –request_id auto -IH1
    • If using HDvM - SN, expand the capacity in the Expand V-VOLs window.
  6. Verify that expanding the S-VOL capacity in the TC pair is finished.

    • If using CCI, raidcom get command_status command to verify that the raidcom extend ldev command is finished processing.

      Command example

      raidcom get command_status -IH1
      raidcom get ldev -ldev_id 0x4444 -fx -IH1

      Verify the expanded LDEV capacity using the raidcom get ldev command.

    • If using HDvM - SN, Select Logical devices from the Storage Systems tree, and then display the LDEV tab. Verify that the capacity with the target LDEV number is correct.
  7. Expand the P-VOL capacity in the TC pair in the same way as the S-VOL capacity.

    If the P-VOL capacity in the TC pair cannot be expanded, see Recovering from failure if one volume capacity in TC pair cannot be expanded.
  8. Verify that expanding the P-VOL capacity in the TC pair is complete in the same way as the S-VOL capacity.

  9. Resynchronize the TC pair.

    If the resync operation in the TC pair cannot be performed, see Recovering from failure if one volume capacity in TC pair cannot be expanded.
  10. Verify that the pair statuses of both the P-VOL and S-VOL in the TC pair have changed to PAIR, and that the volume capacity is not being expanded.

    • If using CCI, check that the P column of the pairdisplay command displays N.
      # pairdisplay -g oradb -fe -fcx
      Group PairVol L/R Port# TID  LU  Seq# LDEV# P/S Status Fence    % P-LDEV# M CTG JID AP EM    E-Seq# E-LDEV# R/W QM DM P
      oradb dev1 L CL5-A-0 30 0 64568 301 P-VOL PAIR NEVER 100 303 - - - 1 - - - -/- - S N
      oradb dev1 R CL5-A-0 30 2 64568 303 S-VOL PAIR NEVER 100 301 - - - - - - - -/- - S N
      oradb dev2 L CL5-A-0 30 1 64568 302 P-VOL PAIR NEVER 100 304 - - - 1 - - - -/- - D N
      oradb dev2 R CL1-A-0 30 3 64568 304 S-VOL PAIR NEVER 100 302 - - - - - - - -/- - D N
      

      The P column in the pairdisplay command displays the status that the volume capacity is being expanded. An N indicates that the volume capacity is not being expanded, an E indicates that the volume capacity is being expanded.

      The E status is displayed after expanding the P-VOL or S-VOL capacity in the TC pair, and before performing the pair resync operation. This status changes to N after the resync operation completes.

    • If using HDvM - SN, check if the Processing Status field in the Remote Replication window is blank.

      Expanding is displayed if the volume capacity is being expanded.

  11. If you temporarily changed the differential data management method from SM difference to hierarchical difference (Step 2), restore to the SM difference management.

    1. To restore to the SM difference management:

      • If using CCI, set the system option mode (SOM) 1198 to OFF and 1199 to ON by using the raidcom modify system_opt command.

        Command example:

        raidcom modify system_opt -system_option_mode system -mode_id 1198 -mode disable
        raidcom modify system_opt -system_option_mode system -mode_id 1199 -mode enable
      • If using HDvM - SN, set the advanced system settings No. 5 to Disable and No.6 to Disable in the Edit Advanced System Settings window.
    2. Suspend the TC pair.

    3. Resynchronize the TC pair.

    4. Display the detailed information about the TC pair on CCI, and then verify that the current differential data management method is the SM difference management.

    5. If using CCI, and the settings of SOMs 1198 and 1199 have been changed, set SOM 1198 to OFF and 1199 to OFF by using the raidcom modify system_opt command.

      Command example:

      raidcom modify system_opt -system_option_mode system -mode_id 1198 -mode disable
      raidcom modify system_opt -system_option_mode system -mode_id 1199 -mode disable

Expansion order policy when TrueCopy pair shares the same volumes with other software

You can expand the capacity of DP-VOLs used in a TC pair and each software pair when a TC pair shares the same volumes with global-active device (GAD), Universal Replicator (UR), ShadowImage (SI), and Thin Image (HTI).

When a TC pair shares the same volumes with other software, the order in which you expand the DP-VOL capacity consists of the following two expansion orders:

  • Expansion order in a point to point configuration of the TC pair
  • Expansion order in a point to point configuration of each software product
GUID-1C110F03-C56B-4D90-A675-5ABD078D7D5E-low.png
  • When a remote replication (TC/UR/GAD) is included, first expand the S-VOL capacity on the end of the remote replication, and then expand the P-VOL capacity. For more information about the specific expansion procedure, see Expanding DP-VOL capacity when TrueCopy pair is used with Universal Replicator.
  • When a remote replication (TC/UR/GAD) shares the same volumes with a local replication (SI/HTI), first expand the capacity of the S-VOL group in the remote replication. The S-VOL group consists of the S-VOL in the remote replication and all volumes in the local replication with which the S-VOL shares the same volume. After expanding the capacity of the S-VOL group in the remote replication, expand the capacity of the P-VOL group in the remote replication. The P-VOL group consists of the P-VOL in the remote replication and all volumes in the local replication with which the P-VOL shares the same volume.

    The expansion order in each group follows the expansion order in the local replication. For more information about the specific expansion procedures, see Expanding DP-VOL capacity when TrueCopy pair is used with ShadowImage and Expanding DP-VOL capacity when TrueCopy pair is used with Thin Image .

  • In the local replication (SI/HTI), expand the capacity in the order from the highest layer to the lowest. The expansion order is not specified for the volumes in the same layer.

Expanding DP-VOL capacity when TrueCopy pair is used with Universal Replicator

You can expand the capacity of DP-VOLs used as pair volumes when a UR pair and a TC pair are created in a 3DC cascade configuration, a 3DC multi-target configuration, or a 3DC delta resync configuration. For more information about the expansion procedure when a TC pair is used with UR, see the Hitachi Universal Replicator User Guide.

Expanding DP-VOL capacity when TrueCopy pair is used with ShadowImage

You can expand the capacity of DP-VOLs used as pair volumes when a TC pair is used with SI. This procedure provides an example for expanding the DP-VOL capacity in a configuration where the SI L1 pair and L2 pair are created for each volume of the P-VOL and S-VOL in the TC pair. For the detailed procedures for verifying the differential data management method, expanding the capacity, and verifying the expansion during the following procedure, see Expanding DP-VOL capacity used in TrueCopy pair .

Before you begin

  • A V-VOL to be expanded is not an external volume.
  • The LDEV format is being performed on a V-VOL to be expanded.
  • A pool containing a V-VOL to be expanded meets any of the following conditions:
    • Normal condition
    • The used capacity of the pool exceeds the depletion threshold
    • The pool is being shrunk
  • When using GAD, TC, or UR, make sure that there is enough software license capacity for the page capacity assigned to the expanded volume capacity before the expansion.
  • A V-VOL to be expanded is created on a valid storage system. See Expanding DP-VOL capacity while keeping pair status.
  • Ensure that the numbers of differential tables and pair tables required after the expansion do not exceed the maximum number allowed on the storage system. For information about calculating the number of tables, see Calculating the numbers of differential and pair tables for each pair.
.

Procedure

  1. Verify that each volume of the P-VOLs and S-VOLs in a TC pair and SI pairs with which the TC pair shares the same volumes meets the prerequisites.

  2. Display the detailed information about the TC pair on CCI.

    Verify whether the current differential data management method is the SM difference management or the hierarchical difference management by a drive.
    • If the SM difference management is applied, proceed to step 3.
    • If the hierarchical difference management is applied, proceed to step 4.
    • If using HDvM - SN, verify the advanced system settings No.5 and No.6.
      • If both the advanced system settings No.5 and No. 6 are set to Disable, the SM difference management is applied. Go to Step 3.
      • If either or both the advanced system settings No.5 and No.6 are set to Enable, the hierarchical difference management is applied. Go to Step 4.
  3. Change the differential data management method to the hierarchical difference management.

    1. Change system settings for hierarchical difference management.

      • If using CCI, set the system option mode (SOM) 1198 to ON and 1199 to OFF by using the raidcom modify system_opt command.

        Command example:

        raidcom modify system_opt -system_option_mode system -mode_id 1198 -mode enable
        raidcom modify system_opt -system_option_mode system -mode_id 1199 -mode disable
      • If using HDvM - SN, set the advanced system settings No. 5 to Enable and No.6 to Disable in the Edit Advanced System Settings window.
  4. Suspend the TC pair and all SI pairs.

  5. Verify the pair statuses of the SI pairs.

    The SI pair volume capacity can be expanded when the SI pairs are in the PSUS or PSUE status. If the pair statuses are not PSUS or PSUE, perform the pair operations, and then make sure that the pair statuses are migrated to PSUS or PSUE.
  6. Expand each volume capacity, and then verify that the expansion is complete in the expansion order shown in the following figure.

    GUID-2B8C4340-E299-41F5-8C56-8CA9CCD1D910-low.png After expanding the first volume capacity (S-VOL in the TC pair), if you cannot expand the DP-VOL capacity in the SI pair, you cannot expand the P-VOL capacity in the TC pair, or resynchronizing the TC pair, make sure to perform the recovery procedure described in Recovering from failure if one volume capacity in TrueCopy pair cannot be expanded.
  7. Resynchronize the TC pair.

  8. Verify that both the pair statuses of the P-VOL and S-VOL in each pair of the TC pair have changed to PAIR.

    In addition, verify that each volume capacity in the TC pair and SI pair is not being expanded.

    The following table shows how the expansion process is displayed.

    Expansion statusCCIHDvM - SN
    P column in the pairdisplay commandProcessing Status field in the Remote Replication or Local Replication window
    Not being expandedNBlank
    Being expandedE*Expanding*
    * This status has been displayed after expanding the P-VOL or S-VOL capacity in the TC pair until performing the pair resync operation. After the resync operation is complete, the status is migrated to the Not being expanded status. In the SI pair, the Being expanded status is displayed for a while (30 seconds or so) after the expansion of the P-VOL and S-VOL capacity is complete. After that, the status is migrated to the Not being expanded status.
  9. In step 2, if the differential data management method is the SM difference management, restore to the SM difference management using the following procedure:

    1. To restore to the SM difference management:

      • If using CCI, set the system option mode (SOM) 1198 to OFF and 1199 to ON by using the raidcom modify system_opt command.

        Command example:

        raidcom modify system_opt -system_option_mode system -mode_id 1198 -mode disable
        raidcom modify system_opt -system_option_mode system -mode_id 1199 -mode enable
      • If using HDvM - SN, set the advanced system settings No. 5 to Disable and No.6 to Disable in the Edit Advanced System Settings window.
    2. Suspend the TC pair.

    3. Resynchronize the TC pair.

    4. Display the detailed information about the TC pair on CCI, and then verify that the current differential data management method is the SM difference management.

    5. If using CCI, and the settings of SOMs 1198 and 1199 have been changed, set SOM 1198 to OFF and 1199 to OFF by using the raidcom modify system_opt command.

      Command example:

      raidcom modify system_opt -system_option_mode system -mode_id 1198 -mode disable
      raidcom modify system_opt -system_option_mode system -mode_id 1199 -mode disable
Calculating the numbers of differential and pair tables for each pair

If a DP-VOL exceeds 4 TB, the differential tables are placed in the hierarchy memory instead of the shared memory, and the differential tables in the shared memory are not used. Therefore, it is not necessary to calculate the number of differential tables for DP-VOLs over 4 TB.

Procedure

  1. Calculate how many differential tables are required for each pair.

    Use the following formulas:
    number-of-differential-tables-for-expansion = number-of-differential-tables-after-expansion - number-of-differential-tables-before-expansion
    number-of-differential-tables-per-pair = ceiling ((volume-capacity [KB] / 256) / 20,448)

    Ensure that the ceiling value enclosed in the parenthesis () is rounded up to the next integer.

  2. Calculate how many pair tables are required for each pair.

    Use the following formulas:
    number-of-pair-tables-for-expansion = number-of-pair-tables-after-expansion - number-of-pair-tables-before-expansion
    number-of-pair-tables-per-pair = ceiling ((number-of-pair-tables-per-pair / 36)

    Ensure that the ceiling value enclosed in the parenthesis () is rounded up to the next integer.

  3. Verify that the following numbers do not exceed the maximum number allowed on the storage system.

    • The total numbers of current pair tables and pair tables required for expanding the capacity
    • The total numbers of current differential tables and differential tables required for expanding the capacity

    You can check the numbers of differential and pair tables in the Local Replication window.

Expanding DP-VOL capacity when TrueCopy pair is used with Thin Image

You can expand the capacity of DP-VOLs used as pair volumes when a TC pair is used with HTI. This procedure provides an example for expanding the DP-VOL capacity in a configuration where the HTI L1 pair and L2 pair are created for each volume of the P-VOL and S-VOL in the TC pair. For the detailed procedures for verifying the differential data management method, expanding the capacity, and verifying the expansion during the following procedure, see Expanding DP-VOL capacity used in TrueCopy pair .

Before you begin

  • A V-VOL to be expanded is not an external volume.
  • The LDEV format is being performed on a V-VOL to be expanded.
  • A pool containing a V-VOL to be expanded meets any of the following conditions:
    • Normal condition
    • The used capacity of the pool exceeds the depletion threshold
    • The pool is being shrunk
  • When using GAD, TC, or UR, make sure that there is enough software license capacity for the page capacity assigned to the expanded volume capacity before the expansion.
  • A V-VOL to be expanded is created on a valid storage system. See Expanding DP-VOL capacity while keeping pair status.
  • A V-Vol to be expanded is not used in a pair with the clone attribute.
  • Ensure that the following numbers required after the expansion do not exceed the maximum number allowed on the storage system:
    • The snapshot estimated manageable capacity
    • The number of cache management devices
    • The subscription limit of the V-VOL capacity

For information about calculating these numbers, see Calculating the snapshot estimated manageable capacity, the numbers of cache management devices, and the subscription limit of the V-VOL capacity.

Procedure

  1. Verify that each volume of the P-VOLs and S-VOLs in a TC pair and HTI pairs with which the TC pair shares the same volumes meets the prerequisites.

  2. Display the detailed information about the TC pair on CCI.

    Verify whether the current differential data management method is the SM difference management or the hierarchical difference management by a drive.
    • If the SM difference management is applied, proceed to step 3.
    • If the hierarchical difference management is applied, proceed to step 4.
    • If using HDvM - SN, verify the advanced system settings No.5 and No.6.
      • If both the advanced system settings No.5 and No. 6 are set to Disable, the SM difference management is applied. Go to Step 3.
      • If either or both the advanced system settings No.5 and No.6 are set to Enable, the hierarchical difference management is applied. Go to Step 4.
  3. Change the differential data management method to the hierarchical difference management.

    1. Change system settings for hierarchical difference management.

      • If using CCI, set the system option mode (SOM) 1198 to ON and 1199 to OFF by using the raidcom modify system_opt command.

        Command example:

        raidcom modify system_opt -system_option_mode system -mode_id 1198 -mode enable
        raidcom modify system_opt -system_option_mode system -mode_id 1199 -mode disable
      • If using HDvM - SN, set the advanced system settings No. 5 to Enable and No.6 to Disable in the Edit Advanced System Settings window.
    2. Suspend the TC pair.

    3. Resynchronize the TC pair.

    4. Display the detailed information about the TC pair on CCI, and then verify that the current differential data management method is the hierarchical difference management.

  4. Suspend the TC pair.

  5. Verify the pair statuses of the HTI pairs.

    The HTI pair volume capacity can be expanded when the HTI pairs are in the PAIR, PSUS or PSUE status. Verify the current pair statuses of the HTI pairs. If the pair statuses are not PAIR, PSUS or PSUE, perform the pair operations, and then make sure that the pair statuses are migrated to PAIR or PSUS.
  6. Expand each volume capacity, and then verify that the expansion is complete in the expansion order shown in the following figure.

    GUID-8DBB795A-9DDF-4BBE-AC21-124D6635A5A0-low.png After expanding the first volume capacity (S-VOL in the UR pair), if you cannot expand the DP-VOL capacity in the HTI pair, you cannot expand the P-VOL capacity in the TC pair, or resynchronizing the TC pair, make sure to perform the recovery procedure described in Recovering from failure if one volume capacity in TrueCopy pair cannot be expanded.
  7. Resynchronize the TC pair.

  8. Verify that both the pair statuses of the P-VOL and S-VOL in each pair of the TC pair have changed to PAIR.

    In addition, verify that each volume capacity in the TC pair and HTI pair is not being expanded.

    The following table shows how the expansion process is displayed.

    Expansion statusCCIHDvM - SN
    P column in the pairdisplay or raidcom get snapshot commandProcessing Status field in the Remote Replication or HTI pairs window
    Not being expandedNBlank
    Being expandedE*Expanding*
    * This status has been displayed after expanding the P-VOL or S-VOL capacity in the TC pair, and before performing the pair resync operation. After the resync operation is complete, the status is migrated to the Not being expanded status. In the HTI pair, the Being expanded status is displayed for a while (30 seconds or so) after the expansion of the P-VOL and S-VOL capacity is complete. After that, the status is migrated to the Not being expanded status.
  9. In step 2, if the differential data management method is the SM difference management, restore to the SM difference management using the following procedure:

    1. To restore to the SM difference management:

      • If using CCI, set the system option mode (SOM) 1198 to OFF and 1199 to ON by using the raidcom modify system_opt command.

        Command example:

        raidcom modify system_opt -system_option_mode system -mode_id 1198 -mode disable
        raidcom modify system_opt -system_option_mode system -mode_id 1199 -mode enable
      • If using HDvM - SN, set the advanced system settings No. 5 to Disable and No.6 to Disable in the Edit Advanced System Settings window.
    2. Suspend the TC pair.

    3. Resynchronize the TC pair.

    4. Display the detailed information about the TC pair on CCI, and then verify that the current differential data management method is the SM difference management.

    5. If using CCI, and the settings of SOMs 1198 and 1199 have been changed, set SOM 1198 to OFF and 1199 to OFF by using the raidcom modify system_opt command.

      Command example:

      raidcom modify system_opt -system_option_mode system -mode_id 1198 -mode disable
      raidcom modify system_opt -system_option_mode system -mode_id 1199 -mode disable
Calculating the snapshot estimated manageable capacity, the numbers of cache management devices, and the subscription limit of the V-VOL capacity

Procedure

  1. Calculate the snapshot estimated manageable capacity required for expanding the capacity of a Thin Image root volume.

    To expand the capacity of a Thin Image root volume, verify that the snapshot estimated manageable capacity is available. Use the following formulas:
    Snapshot-estimated-manageable-capacity-for-root-volume-expansion = Snapshot-estimated-manageable-capacity-after-root-volume-expansion - Snapshot-estimated-manageable-capacity-before-root-volume-expansion
    Snapshot-estimated-manageable-capacity = (Root-volume-capacity [TB] / 2.6 [TB]) x 3,024 [GB] + (168 [GB] x 2 (consumed-shared-memory [GB]))

    Expanding the volumes other than a root volume does not consume the snapshot estimated manageable capacity. You can check the snapshot estimated manageable capacity in the Local Replication window.

  2. Calculate the maximum number of cache management devices required for expanding the capacity of a Thin Image root volume.

    To expand the capacity of a Thin Image root volume, verify that the cache management devices are available.

    Use the following formula:

    number-of-cache-management-devices-for-root-volume-expansion = ceiling ((Root-volume-capacity-after-expansion [TB] / 2.6 [TB])) - ceiling ((Root-volume-capacity-before-expansion [TB] / 2.6 [TB]))

    Ensure that the ceiling value enclosed in the parenthesis () is rounded up to the next integer.

    Expanding the volumes other than a root volume does not consume the cache management devices.

  3. Calculate the V-VOL capacity to be added by expanding the capacity of a Thin Image root volume.

    To expand the capacity of a Thin Image root volume, verify that the capacity after the expansion does not exceed the subscription limit of the V-VOL capacity contained in a DP pool.

    Use the following formula:

    V-VOL-capacity-added-by-root-volume-expansion = Thin Image-pair-capacity-calculated-based-on- root-volume-capacity-after-expansion - Thin Image-pair-capacity-calculated-based-on-root-volume-capacity-before-expansion
    Thin Image-pair-capacity = Σ ceiling ((Root-volume-capacity [MB] × number-of-pairs* × 2  / 42 [MB])) × 42 [MB]+ Σ ceiling ((Root-volume-capacity [MB] × number-of-pairs* × 2 / 2,921,688 [MB])) × 175,434 [MB]

    * Use the maximum number of HTI pairs to be created in the applicable snapshot tree as number-of-pairs instead of the number of pairs currently created in the applicable snapshot tree because the allocated pages are not released if you delete some pairs.

    Ensure that the ceiling value enclosed in the parenthesis () is rounded up to the next integer.

    Expanding the volumes other than a root volume does not add the V-VOL capacity contained in a DP pool in Thin Image.

Expansion order policy in configuration where P-VOL in remote replication shares the same volume with S-VOL in local replication

  1. Expand the volume capacity in the group that includes the S-VOL in the remote replication in the order shown as 1, 2, 3 in the preceding figure.

  2. Expand the volume capacity in the group that includes the P-VOL in the remote replication in the order shown as 4, 5, 6 in the preceding figure.

    Expand the volume capacity in the order from the highest layer to the lowest because the expansion order in the local replication is prioritized. Expand the P-VOL capacity in the local replication first, and then the S-VOL capacity in the local replication that shares the same volume with the P-VOL in the remote replication.

    For example, when an S-VOL in SI shares the same volume with a P-VOL in TC or UR as shown in the preceding figure, expand the volume capacity in the following order:

    1. P-VOL in the SI pair shown as 4 in the figure.
    2. S-VOL in the SI pair (P-VOL in the TC or UR pair) shown as 5 in the figure.
    3. Volumes in the same layer as the S-VOL in the SI pair.
    4. Volumes in the lower layer than the S-VOL in the SI pair.

Expansion order policy in 3DC cascade, 3DC multi-target, or 3DC delta resync configuration with remote replications

When a 3DC cascade, 3DC multi-target, or 3DC delta resync configuration using remote replications is created, first expand the S-VOL capacity on the end of the remote replication, and then expand the P-VOL capacity as shown in the following figures.

  • 3DC cascade configuration

    GUID-E1F91536-351D-4BE8-8782-DF58E5483EE2-low.png

  • 3DC multi-target configuration

    GUID-C5016543-C8F9-4ED9-8CA7-77384707CFAB-low.png

  • 3DC delta resyc configuration

    GUID-A0B28F5B-C749-429B-B086-B61D6A174B1F-low.png

Expansion order when remote replications in a 3DC cascade configuration share the same volumes with local replications (ShadowImage/Thin Image)

When the remote replications in a 3DC configuration share the same volumes with the local replications (SI/HTI), expand the volume capacity in each following group in the order as shown in the figure.

GUID-0F26984D-4589-428E-B97E-A546C507B91D-low.png

The expansion order in each group follows the expansion order in the local replication. In a 3DC multi-target or 3DC delta resync configuration, expand the volume capacity in the same way.

Procedure

  1. Expand the S-VOL group that consists of the S-VOL in the remote replication and all volumes in the local replication with which the S-VOL shares the same volume.

  2. Expand the P-VOL group that consists of the P-VOL in the remote replication and all volumes in the local replication with which the P-VOL shares the same volume.

Recovering from failure if one volume capacity in TrueCopy pair cannot be expanded

If only one volume capacity in a TC pair can be expanded while the other cannot be expanded, the resync operation in the TC pair cannot be performed after the expansion because the capacity of both of the volumes is not the same.

When a TC pair is used with GAD, UR, SI, or HTI, if the capacity of the P-VOL and the S-VOL of one of the software products cannot be expanded, which causes the invalid state that the expansion of the entire volume capacity is not complete. Perform the following operation to recover from the invalid state.

Procedure

  1. Verify that all of the prerequisites are met.

    If the prerequisites are not met, proceed to step 4.
    1. Verify that both the P-VOL and S-VOL in a TC pair meet the prerequisites for expanding the DP-VOL capacity.

      See the prerequisites for Expanding DP-VOL capacity used in TrueCopy pair .

    2. Verify that all of the volumes meet the prerequisites for expanding the capacity in each of the software products.

      When a TC pair is used with GAD, UR, SI, or HTI, the capacity of the P-VOLs and the S-VOLs used in all of the used software products must be expanded.
  2. When the prerequisites for expanding the DP-VOL capacity are met, retry the expansion and make sure that the capacity of the P-VOL and S-VOL in the TC pair is the same.

    1. If there is not enough free space, increase the free space, and then expand the DP-VOL capacity.

    2. If a TC pair is used with GAD, UR, SI, or HTI, or when a 3DC configuration is created with three UR sites, retry the expansion and make sure that the capacity of the P-VOL and S-VOL in each of the software products is the same.

    • If you can expand the capacity, go to Step 3.
    • If you cannot expand the capacity, go to Step 4.
  3. Resynchronize the TC pair

    As a result, the recovery procedure from the failure is complete.
  4. Delete the TC pair, expand the volume capacity in the SMPL status, and then re-create the TC pair.

    • If you want to restore to the conditions before the expansion due to a capacity input error and others, delete the TC pair, and then recreate the LDEV with the correct capacity. After that, recreate the TC pair.
    • If a TC pair is used with GAD or UR, delete all pairs, expand the volume capacity in the SMPL status, and then restore the configurations by following the procedure for creating the configurations.

      If you want to restore to the conditions before the expansion due to a capacity input error and others, delete all pairs, and then recreate the LDEV with the correct capacity. After that, restore the configurations by following the procedure for creating the configurations.

    • If a TC pair is used with SI or HTI, and the capacity of the P-VOL and S-VOL in a SI pair or HTI pair is not the same, you can only delete the SI pair or HTI pair. You can read the S-VOL data in the SI pair or HTI pair before the expansion. If you want to use the data before the expansion, delete all pairs after the data reading is complete. Expand the volume capacity in the SMPL status, and then restore the configurations by following the procedure for creating the configurations.

      If you want to restore to the conditions before the expansion due to a capacity input error and others, delete all pairs, and then recreate the LDEV with the correct capacity. After that, restore the configurations.

Recovering from failure if one volume capacity in TrueCopy pair has been expanded

You can recover from a failure if only one volume capacity in a TC pair can be expanded, while a failure occurs on the other volume before the expansion.

Procedure

  1. Start to recover from the failure using one of the TC disaster recovery operations.

    Depending on the operations during the recovery procedure, one or more of the following actions are required:
    • If the operation is resynchronizing a TC pair

      The resynch operation cannot be performed because the capacity of the P-VOL and S-VOL in the TC pair is not the same.

      Complete Steps 2 and 3 before the TC pair resynch operation.

    • If the operation is,
      • Deleting a TC pair
      • Recovering from a volume failure
      • Re-creating a TC pair

      The TC pair cannot be created because the capacity of the target P-VOL and S-VOL is not the same when re-creating the TC pair.

      Complete Steps 2 and 3 immediatelybefore the TC pair resynch operation.

    • If the operation is,
      • Deleting a TC pair
      • Deleting a volume
      • Creating a volume
      • Re-creating a TC pair

      The TC pair cannot be created because the capacity of the target P-VOL and S-VOL is not the same when re-creating the TC pair. Make sure that the capacity of the P-VOL and S-VOL is the same when creating the volumes.

      Skip Steps 2 and 3.

  2. Expand the capacity of volumes whose capacity is not expanded, and then make sure that the capacity of the P-VOL and S-VOL in the TC pair is the same.

    When a TC pair is used with other software, the capacity of the P-VOLs and S-VOLs in all of the used software products must be expanded. For more information about the order in which the volume capacity is expanded, see Expansion order policy when TrueCopy pair shares the same volumes with other software.
  3. Restart the resync operation and the creation of the TC pair by following one of the TC disaster recovery operations.

Managing power-off for systems and network devices

You might have to have a planned outage of the primary system, the secondary system, or both to maintain the systems.

Though you are responsible for controlling power-off activities, it is advisable to check with customer support.

How powering off for a planned outage affects primary and secondary systems

Before you power off a primary or secondary system for a planned outage, you should understand how powering off primary or secondary systems affects those systems.

Review the following system behaviors regarding powering off:

  • TC pairs are not affected when power is removed from a primary system while operations are in progress.
  • When power is restored on the primary system, the system communicates with the secondary systems to confirm S-VOL pair status(es). Make sure that TC communications are fully restored (all paths have normal status) before beginning I/O operations to the P-VOL.

    If the primary system accepts an I/O for a P-VOL when the path status is not normal, the primary system will split the pair. P-VOL status will change to PSUE (by RCU) or Suspend (by RCU) but the primary system cannot change the pair status of the S-VOL.

  • If power is removed from a secondary system or from a data path component while TC operations are in progress, the primary system detects the communication failure, splits all affected pairs, and generates SIMs reporting the failures. The primary system changes the P-VOL status to PSUE (by RCU) or Suspend (by RCU) but cannot change the status of the S-VOLs.
  • If a primary or secondary system is powered off and the backup batteries are fully discharged while pairs are split, differential data is retained to SSD. In this unlikely case, primary system copies differential data to secondary system when the pairs are resynchronized.

Planned outage of the primary system

A planned outage of the primary system does not affect TrueCopy.

Planned outage of the secondary system or remote path

You must split the pairs in a secondary system prior to a planned outage of the system or to a data path component (for example, switch, channel extender).

Procedure

  1. Identify the P-VOLs that are paired with S-VOL in the secondary system that is to be powered off.

    For data path outage, identify all P-VOLs in the primary system that use the path or component to be powered off. You need to know the primary system, CU, and IDs (port, host group or iSCSI target, and LUN) for each of the P-VOLs.
    1. When powering off storage systems at the secondary site, identify all P-VOLs paired with the S-VOLs of storage systems to be powered off.

    2. When powering off remote copy connections, identify all P-VOLs of storage systems at the primary site that use paths, switches, or channel extenders to be powered off.

  2. Connect to each primary system that contains to-be-affected P-VOLs, and split all to-be-affected pairs.

    Confirm the changed pair status in the Remote Replication window or the View Pair Properties window in HDvM - SN or by using the pairdisplay command in CCI.
  3. Perform the planned outage of the secondary system or remote copy connections.

  4. When the secondary system is fully powered on and ready, resynchronize the affected pairs at each primary system. Confirm the pair status changes.

Planned outage of both primary and secondary systems

When you plan an outage of a TrueCopy primary and secondary systems at the same time, the primary system must be powered off first, and then powered on last.

Procedure

  1. Perform the planned outage of the primary system first. Because a planned outage does not affect pairs, nothing out of the ordinary must be done regarding the TC system or operations. Do not power on the primary system at this time.

  2. If a secondary system to be powered off is connected to a primary system that is not powered off, split the pairs before powering off the secondary system. Confirm that the pair status changes.

  3. Perform the planned outage of the secondary systems as described in Planned outage of the secondary system or remote path.

  4. Power on the secondary systems. Make sure that secondary systems and remote connections are fully operational and ready to resynchronize operations before powering on the primary system.

  5. Power on the primary system, and make sure the primary storage system and remote connections are operational and ready to resynchronize operations. If you split any pairs in step 2, you can also resynchronize those pairs now.