System requirements
You should understand all requirements and restrictions for global-active device operations.
Requirements and restrictions
The following table lists the requirements and restrictions for global-active device operations.
Item |
Requirements and restrictions |
Primary and secondary storage systems |
|
GAD 3DC delta resync (GAD+UR) |
|
External storage systems or servers (for quorum disk) |
|
Licensed capacity |
|
Host server platforms |
|
Maximum number of storage systems that can be connected |
One storage system can create pairs with a maximum of 15 storage systems. |
SCSI commands |
|
Physical paths connecting the primary and secondary storage systems |
|
Remote paths and path groups |
|
Virtual storage machines (VSMs) |
|
Resource groups (VSP G1x00 and VSP F1500) |
|
Maximum number of GAD pairs |
|
Pair volumes |
|
Quorum disks |
|
Consistency groups |
|
Alternate path software |
Alternate path software is required for the single-server GAD configuration and the cross-path GAD configuration (two servers). When ALUA is used in the cross-path configuration, use the same models at both the primary and secondary sites. The following microcode/firmware is required in the storage systems at the primary and secondary sites: DKCMAIN version 80-03-31-00/00 or later for VSP G1x00 and VSP F1500. Refer to the Hitachi Vantara interoperability matrix: https://support.hitachivantara.com/en_us/interoperability.html |
Cluster software |
Cluster software is required for the server-cluster and cross-path GAD configurations. Refer to the Hitachi Vantara interoperability matrix: https://support.hitachivantara.com/en_us/interoperability.html |
User interfaces |
|
Interoperability requirements
You should understand how global-active device (GAD) operates with other features of the VSP G1000, VSP G1500, VSP F1500, VSP G350, VSP G370, VSP G700, VSP G900, VSP F350, VSP F370, VSP F700, VSP F900 storage systems.
Volume types that can be used for GAD
Knowing the volume types available with other features and whether the volume can be used for GAD operations helps you to operate GAD successful.
Volume type |
Used as GAD P-VOL? |
Used as GAD S-VOL? |
Used as quorum disk? |
Dynamic Provisioning / Dynamic Tiering / Active flash | |||
Virtual volume |
Yes1 |
Yes1 |
No |
Pool volume |
No |
No |
No |
V-VOL with capacity saving enabled |
Yes |
Yes |
No |
Deduplication system data volume |
No |
No |
No |
ShadowImage / Thin Image2 | |||
P-VOL |
Yes |
Yes |
No |
S-VOL |
No |
No |
No |
TrueCopy | |||
P-VOL |
No |
No |
No |
S-VOL |
No |
No |
No |
Universal Replicator | |||
P-VOL |
Yes |
Yes3 |
No |
S-VOL |
No |
No |
No |
Journal volume |
No |
No |
No |
Universal Volume Manager | |||
External volume |
Yes1 |
Yes1 |
Yes |
Data Retention Utility | |||
Volume with access attribute |
Yes |
Yes4 |
No |
Volume Migration | |||
Source volume |
No (VSP Gx00 models and VSP Fx00 models) Yes (VSP G1x00 and VSP F1500) |
No (VSP Gx00 models and VSP Fx00 models) Yes (VSP G1x00 and VSP F1500) |
No |
Target volume |
No |
No |
No |
Cache Residency Manager (VSP G1x00 and VSP F1500) | |||
The volume on which Cache Residency Manager is set |
No |
No |
No |
Hitachi Virtual LUN | |||
Virtual LUN volume |
Yes |
Yes |
Yes5 |
LUN Manager | |||
The volume on which paths are defined |
Yes |
Yes |
No |
Volume on which paths are not defined |
No |
No |
Yes |
CCI command device | |||
Command device |
No |
No |
No |
Remote command device |
No |
No |
No |
Encryption License Key | |||
Volume whose parity groups have been encrypted |
Yes |
Yes |
You can use an encrypted volume in the external storage system as a quorum disk.6 |
Volume which is being migrated |
Yes |
No |
No |
Notes:
|
Dynamic Provisioning / Dynamic Tiering / Active flash
Dynamic Provisioning, Dynamic Tiering, and active flash virtual volumes (DP-VOLs) can be used as GAD pair volumes.
A V-VOL with capacity saving enabled can be used as a P-VOL or S-VOL of a GAD pair. A deduplication system data volume cannot be used as a P-VOL or S-VOL of a GAD pair.
- Data compressed or deduplicated by the capacity saving function is copied to a volume after compression and deduplication are released, that is, the capacity saving function is not performed immediately for copied data. Therefore, before creating or resynchronizing a GAD pair, make sure that the available capacity in the copy destination volume is greater than the used capacity in the copy origination volume before capacity saving. For details, see the Provisioning Guide for Open Systems.
- If you create a GAD pair using a volume for which the capacity saving function is used, compressed or deduplicated data is copied. Because of this, copy or I/O performance might be degraded.
- When the capacity saving function is used, management information is stored in a pool. As a result, there might be a difference in the number of used pages or licensed capacity between a P-VOL and an S-VOL.
ShadowImage
You can use the GAD P-VOL and S-VOL as a ShadowImage P-VOL.
You can create up to three ShadowImage pairs respectively on the GAD primary and secondary storage systems.

Because the server recognizes a GAD pair as one volume, it sees the volume as paired with six ShadowImage volumes.

You can create three additional, cascaded SI pairs using the SI S-VOLs. This means that up to nine SI pairs can be created with the GAD P-VOL, and nine SI pairs can be created with the GAD S-VOL.

- Pairs in an SI consistency group must reside in the same storage system. Because of this, the SI pairs that are associated with both the GAD P-VOL and the S-VOL cannot be registered to the same consistency group.
- When you use GAD pair volumes to create an SI pair, you must specify the physical LDEV ID, not the virtual LDEV ID.
Limitations when sharing GAD and ShadowImage volumes
Any operation that deletes the virtual LDEV ID of a volume used as a ShadowImage volume cannot be performed.
When a GAD pair is deleted with the P-VOL specified, the virtual LDEV ID of the S-VOL is deleted. If you delete the pair with the S-VOL specified, the virtual LDEV ID of the P-VOL is deleted. When the virtual LDEV ID is deleted, the server does not recognize the volume.
SI operations and GAD pair status
The ability to perform a ShadowImage pair operation depends on the SI pair status and GAD pair status.
The following tables show SI pair operations and whether they can be performed (Yes, No) with the listed GAD status. The information assumes the required SI status for the operation.
The Virtual LDEV ID column shows whether the volume has a virtual LDEV ID or not (Yes, No).
GAD pair status |
Virtual LDEV ID |
I/O |
ShadowImage pair operation | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs/Suspend copy | ||
SMPL |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
No |
No |
No |
Yes |
Yes |
Yes |
Yes |
Yes | |
No, but the GAD reserve attribute is set |
No |
No |
No |
No |
No |
No |
Yes |
GAD pair status |
I/O mode |
Pair location |
I/O |
ShadowImage pair operation | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs/Suspend copy | |||
INIT/COPY |
Mirror (RL) |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
No1 |
Yes |
Block |
Secondary |
No |
No |
Yes |
No2 |
No2 |
No1, 3 |
Yes | |
COPY |
Mirror (RL) |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
No1 |
Yes |
Block |
Secondary |
No |
No |
Yes |
No2 |
No2 |
No1, 3 |
Yes | |
Notes:
|
GAD pair status |
I/O mode |
Pair location |
I/O |
ShadowImage pair operation | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs/Suspend copy | |||
PAIR |
Mirror (RL) |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
No* |
Yes |
Secondary |
Yes |
Yes |
Yes |
Yes |
Yes |
No* |
Yes | ||
* Cannot be used because GAD pairs are not suspended, and also because the volume at the GAD copy destination is the same as the volume at the ShadowImage copy destination. |
GAD pair status |
I/O mode |
Pair location |
I/O |
ShadowImage pair operation | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs/Suspend copy | |||
Microcode version 80-04-2x or earlier (VSP G1x00 and VSP F1500) | |||||||||
PAIR |
Mirror(RL) |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
No* |
Yes |
Block |
Secondary |
No |
No |
Yes |
Yes |
Yes |
No* |
Yes | |
Microcode version 80-05-0x or later (VSP G1x00 and VSP F1500), firmware version 88-01-0x or later (VSP G350, G370, G700, G900 and VSP F350, F370, F700, F900) | |||||||||
PAIR |
Mirror(RL) |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
No* |
Yes |
Mirror(RL) |
Secondary |
Yes |
Yes |
Yes |
Yes |
Yes |
No* |
Yes | |
* Cannot be used because GAD pairs are not suspended, and also because the volume at the GAD copy destination is the same as the volume at the ShadowImage copy destination. |
GAD pair status |
I/O mode |
Pair location |
I/O |
ShadowImage pair operation | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs/Suspend copy | |||
PSUS |
Local |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes* |
Yes |
Block |
Primary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes | |
PSUE |
Local |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes* |
Yes |
Block |
Primary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes | |
Secondary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes | ||
SSUS |
Block |
Secondary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes |
SSWS |
Local |
Secondary |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes* |
Yes |
* Quick Restore cannot be executed. For VSP G1x00 and VSP F1500, if the microcode is 80-05-7x or later, Quick Restore can be executed. |
GAD pair status |
I/O mode |
Pair location |
I/O |
SI pair operations | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs/Suspend copy | |||
PSUE |
Block |
Primary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes |
Secondary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes |
GAD operations and SI pair status
The ability to perform a GAD pair operation depends on GAD pair status and SI pair status.
The following tables show GAD operations and whether they can be performed (Yes, No) with the listed SI status. The information assumes the required GAD status for the operation.
SI pair status |
GAD pair operations | |||||||
Create pairs |
Suspend pairs |
Delete pairs |
Resync pairs | |||||
P-VOL selected |
S-VOL selected |
P-VOL selected1 |
S-VOL selected2 |
Forced deletion |
P-VOL selected |
S-VOL selected | ||
SMPL(PD) |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
COPY |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
PAIR |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
COPY(SP) |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
PSUS(SP) |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
PSUS |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
COPY(RS) |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
COPY(RS-R) |
No4 |
impossible |
impossible |
Yes |
No3 |
Yes |
No4 |
No4 |
PSUE |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
Notes:
|
SI pair status |
GAD pair operations | |||||||
Create pairs |
Suspend pairs |
Delete pairs |
Resync pairs | |||||
P-VOL selected |
S-VOL selected |
P-VOL selected1 |
S-VOL selected2 |
Forced deletion |
P-VOL selected |
S-VOL selected | ||
SMPL(PD) |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
COPY |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
PAIR |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
COPY(SP) |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
PSUS(SP) |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
PSUS |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
COPY(RS) |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
COPY(RS-R) |
No3, 5 |
impossible |
impossible |
No4 |
Yes |
Yes |
No5, 6 |
No6 |
PSUE |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
Notes:
|
Thin Image
You can use a GAD P-VOL or S-VOL as a Thin Image (HTI) P-VOL.
You can create up to 1,024 Thin Image pairs using a GAD P-VOL, and up to 1,024 Thin Image pairs using a GAD S-VOL.

Because the server recognizes the GAD pair as one volume, it sees the volume as paired with 2,048 HTI volumes.

- Pairs in an HTI consistency group and snapshot group must reside in the same storage system. Because of this, the HTI pairs that are associated with both the GAD P-VOL and S-VOL cannot be registered to the same consistency group or snapshot group.
- When you use GAD pair volumes to create a Thin Image pair, specify the physical LDEV ID, not the virtual LDEV ID.
Limitations for using both GAD and Thin Image
Any operation that deletes the virtual LDEV ID of a volume used as a Thin Image volume cannot be performed.
When a GAD pair is deleted with the P-VOL specified, the virtual S-VOL's LDEV ID is deleted. If you delete the pair with the S-VOL specified, the P-VOL's virtual LDEV ID is deleted. When the virtual LDEV ID is deleted, the server does not recognize the volume, making it unusable as a Thin Image volume.
Thin Image operations and GAD status
The ability to perform a Thin Image pair operation depends on the HTI pair status and the GAD pair status.
The following tables show HTI operations and whether they can be performed (Yes, No) with the listed GAD status. The information assumes the required HTI status for the operation.
The Virtual LDEV ID column shows whether the volume has a virtual LDEV ID or not (Yes, No).
GAD pair status |
Virtual LDEV ID |
I/O |
Thin Image pair operation | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs | ||
SMPL |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
No |
No |
No |
Yes |
Yes |
Yes |
Yes |
Yes | |
No, but the GAD reserve attribute is set |
No |
No |
No |
No |
No |
No |
Yes |
GAD pair status |
I/O mode |
Pair location |
I/O |
Thin Image pair operation | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs | |||
INIT/COPY |
Mirror (RL) |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
No1 |
Yes |
Block |
Secondary |
No |
No |
No |
No2 |
No2 |
No1, 3 |
Yes | |
COPY |
Mirror (RL) |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
No1 |
Yes |
Block |
Secondary |
No |
No |
No |
No2 |
No2 |
No1, 3 |
Yes | |
Notes:
|
GAD pair status |
I/O mode |
Pair location |
I/O |
Thin Image pair operation | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs | |||
PAIR |
Mirror (RL) |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
No* |
Yes |
Secondary |
Yes |
Yes |
Yes |
Yes |
Yes |
No* |
Yes | ||
* Cannot be used because GAD pairs are not suspended, and also because the volume at the GAD copy destination is the same as the volume at the Thin Image copy destination. |
GAD pair status |
I/O mode |
Pair location |
I/O |
Thin Image pair operation | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs/Suspend copy | |||
Microcode version 80-04-2x or earlier (VSP G1x00 and VSP F1500) | |||||||||
PAIR |
Mirror (RL) |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
No* |
Yes |
Block |
Secondary |
No |
No |
Yes |
Yes |
Yes |
No* |
Yes | |
Microcode version 80-05-0x or later (VSP G1x00 and VSP F1500), firmware version 88-01-0x or later (VSP G350, G370, G700, G900 and VSP F350, F370, F700, F900) | |||||||||
PAIR |
Mirror(RL) |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
No* |
Yes |
Mirror(RL) |
Secondary |
Yes |
Yes |
Yes |
Yes |
Yes |
No* |
Yes | |
* Cannot be used because GAD pairs are not suspended, and also because the volume at the GAD copy destination is the same as the volume at the Thin Image copy destination. |
GAD pair status |
I/O mode |
Pair location |
I/O |
Thin Image pair operation | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs | |||
PSUS |
Local |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Block |
Primary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes | |
PSUE |
Local |
Primary |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Yes |
Block |
Primary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes | |
Secondary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes | ||
SSUS |
Block |
Secondary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes |
SSWS |
Local |
Secondary |
Yes |
Yes |
Yes |
Yes |
Yes |
No |
Yes |
GAD pair status |
I/O mode |
Pair location |
I/O |
Thin Image pair operation | |||||
Read |
Write |
Create pairs |
Split pairs |
Resync pairs |
Restore pairs |
Delete pairs | |||
PSUE |
Block |
Primary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes |
Secondary |
No |
No |
Yes |
Yes |
Yes |
No |
Yes |
GAD operations and Thin Image pair status
The ability to perform a GAD pair operation depends on the GAD pair status and the HTI pair status.
The following tables show GAD operations and whether they can be performed (Yes, No) with the listed HTI status. The information assumes the required GAD status for the operation.
TI pair status |
GAD pair operations | |||||||
Create GAD Pairs |
Suspend Pairs |
Delete Pairs |
Resync Pairs | |||||
P-VOL specified |
S-VOL specified |
P-VOL specified1 |
S-VOL specified2 |
Forced deletion |
P-VOL specified |
S-VOL specified | ||
SMPL(PD) |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
COPY |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
PAIR |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
PSUS |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
COPY(RS-R) |
No4 |
impossible |
impossible |
Yes |
No3 |
Yes |
No4 |
No4 |
PSUE |
Yes |
Yes |
Yes |
Yes |
No3 |
Yes |
Yes |
Yes |
Notes:
|
TI pair status |
GAD pair operations | |||||||
Create GAD Pairs |
Suspend Pairs |
Delete Pairs |
Resync Pairs | |||||
P-VOL specified |
S-VOL specified |
P-VOL specified1 |
S-VOL specified2 |
Forced deletion |
P-VOL specified |
S-VOL specified | ||
SMPL(PD) |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
COPY |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
PAIR |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
PSUS |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
COPY(RS-R) |
No3, 5 |
No |
No |
No4 |
Yes |
Yes |
No5, 6 |
No6 |
PSUE |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
Yes |
Yes |
Notes:
|
Use cases for pairing GAD volumes with SI or HTI
Backing up GAD pair volumes with ShadowImage (SI) or Thin Image (HTI) provides further protection for GAD data.
Further protection for GAD data is provided in the following ways:
- When the GAD pair is resynchronized, pair status changes to COPY. While in this status, S-VOL consistency is temporarily lost. You can protect data when in COPY status by pairing the S-VOL with SI or HTI before resynchronizing the GAD pair.
- Though data in a blocked GAD pair is inconsistent, host activity can continue with the P-VOL or S-VOL. Therefore, before correcting the failure by forcibly deleting the pair, you should pair the volumes with SI or HTI.
- The SI and HTI pairs can then be copied, and the copies used for other purposes.
Universal Replicator
You can combine GAD and Universal Replicator to create a configuration that can continue to operate in the event of a multi-site failure.
In a GAD system, the server accesses the primary and secondary sites simultaneously and shares the same data between the two sites (at campus distance). If a failure occurs at one site, you can continue operations at the other site. However, if a failure occurs at both sites, for example due to a large-scale disaster, you will not be able to continue operations with the data redundancy provided only by GAD.
To manage this situation, you can implement a 3-data-center (3DC) configuration by combining GAD and Universal Replicator (UR). This configuration is called a GAD 3DC delta resync (GAD+UR) configuration. If there is a failure at both the primary site and the GAD secondary site, the GAD+UR configuration enables you to continue operations using the UR secondary site (at metro distance).
- When all storage systems in a GAD+UR configuration are VSP G1x00 and VSP F1500, the DKCMAIN microcode version must be 80-02-4-xx/xx or later. If both VSP G1000, VSP G1500, VSP F1500 and VSP G800 or VSP F800 exist, the DKCMAIN firmware version for VSP G1x00 and VSP F1500 must be 80-04-xx-xx/xx or later; and for VSP G800, the DKCMAIN firmware version must be 83-03-xx-xx/xx or later, or for VSP F800, the DKCMAIN firmware version must be 83-04-2x-xx/xx or later. You cannot combine GAD and UR using other storage system models.
- If both VSP F800 and VSP G1000, VSP G1500, VSP F1500 exist, the DKCMAIN microcode version for VSP G1000, VSP G1500, and VSP F1500 must be 80-04-xx-xx/xx or later, and for VSP F800, the DKCMAIN firmware version must be 83-04-2x-xx/xx or later.
- The CCI remote command device is not required in GAD+UR configurations.
- Volumes in a 3DC
GAD+UR configuration cannot be shared with the following volumes:
- UR volumes in a system with multiple storage systems in the primary and secondary sites
- UR volumes in a 3DC multi-target configuration with TC and UR
- UR volumes in a 3DC multi-target configuration with 3 UR sites
- UR volumes in a 3DC cascade configuration with 3 UR sites
- 3DC multi-target configuration and 3DC cascade configuration with GAD and UR are supported only by VSP G900, VSP F900, VSP G1x00 and VSP F1500.
The following figure shows the required configuration for GAD+UR operations. You must use this configuration when combining GAD with UR.

In a GAD+UR configuration:
- The P-VOL of the GAD pair functions as the P-VOL of the UR pair.
- The S-VOL of the GAD pair functions as the P-VOL of the UR delta resync pair.
- The UR S-VOL has two mirror IDs, one for the UR pair, and one for the UR delta resync pair.
- The UR delta resync pair consists of the GAD S-VOL at the GAD secondary site and the UR S-VOL at the UR secondary site. This UR delta resync pair allows you to synchronize the UR pair S-VOL by using the journal data at the GAD secondary site in the event of a failure at the primary site.
GAD pair and Universal Replicator pair interoperability
You should know how GAD pairs and Universal Replicator pairs work together for different pair statuses for GAD pairs or UR pairs.
The following table shows GAD pair operations and whether they can be performed (Yes or No) with the listed UR pair status.
UR pair status | Attribute of the target UR pair | GAD pair operation | |||||
Create pairs1 | Split pairs | Suspend pairs | Resynchronize pairs | Delete pairs | |||
P-VOL specified | S-VOL specified | P-VOL specified | S-VOL specified | P-VOL or S-VOL specified | |||
COPY |
P-VOL |
No |
Yes |
impossible |
Yes |
Yes |
No2 |
S-VOL |
No |
No3 |
impossible |
No |
impossible |
No2 | |
PAIR |
P-VOL |
No |
Yes |
impossible |
Yes |
Yes |
No2 |
S-VOL |
No |
No3 |
impossible |
No |
impossible |
No2 | |
PSUS |
P-VOL |
No |
Yes |
impossible |
Yes |
Yes |
No2 |
PSUE |
P-VOL |
No |
Yes |
impossible |
Yes |
Yes |
No2 |
S-VOL |
No |
No3 |
impossible |
No |
impossible |
No2 | |
SSUS |
S-VOL |
No |
No3 |
impossible |
No |
impossible |
No2 |
SSWS |
S-VOL |
No |
No3 |
impossible |
No |
impossible |
No2 |
HOLD |
P-VOL |
No |
impossible |
Yes |
impossible |
impossible |
No2 |
S-VOL |
No |
impossible |
impossible |
impossible |
impossible |
No2 | |
HLDE |
P-VOL |
No |
impossible |
Yes |
impossible |
impossible |
No2 |
S-VOL |
No |
impossible |
impossible |
impossible |
impossible |
No2 | |
Note:
|
The following table shows UR pair operations and whether they can be performed (Yes or No) with the listed GAD pair status.
GAD pair status | I/O mode | Attribute of the target GAD pair | UR pair operation | ||||
Create pairs | Split pairs | Suspend pairs | Resynchronize pairs | ||||
P-VOL specified | S-VOL specified | P-VOL specified | S-VOL specified | ||||
INIT/COPY |
Mirror (RL) |
P-VOL |
No |
Yes |
impossible |
Yes1 |
impossible |
Block |
S-VOL |
No |
impossible |
impossible |
impossible |
impossible | |
COPY |
Mirror (RL) |
P-VOL |
No |
Yes |
impossible |
Yes1 |
impossible |
Block |
S-VOL |
No |
impossible |
impossible |
impossible |
impossible | |
PAIR |
Mirror (RL) |
P-VOL |
Yes2 |
Yes |
impossible |
Yes1 |
impossible |
S-VOL |
No |
impossible |
impossible |
impossible |
impossible | ||
PSUS |
Local |
P-VOL |
No |
Yes |
Yes3 |
Yes1 |
Yes3 |
Block |
P-VOL |
No |
Yes |
Yes3 |
No |
impossible | |
PSUE |
Local |
P-VOL |
No |
Yes |
Yes3 |
Yes1 |
Yes3 |
Block |
P-VOL |
No |
Yes |
Yes3 |
No |
impossible | |
SSUS |
Block |
S-VOL |
No |
impossible |
impossible |
impossible |
impossible |
SSWS |
Local |
S-VOL |
No |
Yes |
impossible |
Yes |
impossible |
Note:
|
The following table shows UR delta resync pair operations and whether they can be performed (Yes or No) with the listed GAD pair status.
GAD pair status | I/O mode | Attribute of the target GAD pair | UR delta resync pair operation | |||||
Create UR delta resync pair | Delta resync | Delete pairs | ||||||
P-VOL specified | S-VOL specified | UR delta resync P-VOL | UR delta resync S-VOL | |||||
INIT/COPY |
Mirror (RL) |
P-VOL |
No |
No1 |
Yes |
impossible |
impossible |
impossible |
Block |
S-VOL |
No |
No1 |
impossible |
impossible |
impossible |
impossible | |
COPY |
Mirror (RL) |
P-VOL |
No |
No1 |
Yes |
impossible |
impossible |
impossible |
Block |
S-VOL |
No |
No1 |
impossible |
impossible |
impossible |
impossible | |
PAIR |
Mirror (RL) |
P-VOL |
No |
No1 |
Yes |
impossible |
impossible |
impossible |
S-VOL |
Yes |
No1 |
impossible |
impossible |
Yes4 |
impossible | ||
PSUS |
Local |
P-VOL |
No |
No1 |
Yes |
Yes3 |
Yes4 |
impossible |
Block |
P-VOL |
Yes2 |
No1 |
Yes |
Yes3 |
Yes4 |
impossible | |
PSUE |
Local |
P-VOL |
No |
No1 |
Yes |
Yes3 |
Yes4 |
impossible |
Block |
P-VOL |
Yes2 |
No1 |
Yes |
Yes3 |
Yes4 |
impossible | |
SSUS |
Block |
S-VOL |
No |
No1 |
impossible |
impossible |
Yes4 |
impossible |
SSWS |
Local |
S-VOL |
No |
No1 |
Yes |
impossible |
Yes4 |
impossible |
Note:
|
Data Retention Utility
You can create a GAD pair using volumes that have been assigned the Data Retention Utility access attribute.
- When you create or resynchronize a GAD pair, the access attribute set for the P-VOL is copied to the S-VOL.
- If you change the access attribute when GAD status is Mirrored or Mirroring, make sure to set the access attribute to both the P-VOL and S-VOLs.
- Server I/O can be controlled, depending on GAD status and the access attribute.
- If you set the Data Retention Utility S-VOL Disable attribute on the GAD S-VOL, GAD pair operations using CCI are restricted. Release the S-VOL Disable attribute from the S-VOL, then perform CCI operations.
GAD status and I/O allowance by access attribute
Even when the access attribute is assigned to a GAD volume, the initial copy and pair resynchronization operations are not controlled. The following table shows whether server I/O is allowed for the listed GAD status and access attribute.
GAD statuses |
Access attribute |
I/O | ||
P-VOL |
S-VOL |
P-VOL |
S-VOL | |
Mirrored |
Read/Write |
Read/Write |
Ends normally |
Ends normally |
Read Only or Protect |
Read/Write |
Depends on the attribute* |
Ends normally | |
Read/Write |
Read Only or Protect |
Ends normally |
Depends on the attribute* | |
Read Only or Protect |
Read Only or Protect |
Depends on the attribute* |
Depends on the attribute* | |
Quorum disk blocked (status of GAD pairs created, resychronized, or swap resynchronized on 80-04-2x or earlier for VSP G1x00 and VSP F1500) |
Read/Write |
Read/Write |
Ends normally |
Rejected |
Read Only or Protect |
Read/Write |
Depends on the attribute* |
Rejected | |
Read/Write |
Read Only or Protect |
Ends normally |
Rejected | |
Read Only or Protect |
Read Only or Protect |
Depends on the attribute* |
Rejected | |
Quorum disk blocked (status of GAD pairs created, resychronized, or swap resynchronized on 80-05-0x or later for VSP G1x00 and VSP F150088-01-0x or later for VSP G350, G370, G700, G900 and VSP F350, F370, F700, F900) |
Read/Write |
Read/Write |
Ends normally |
Ends normally |
Read Only or Protect |
Read/Write |
Depends on the attribute* |
Ends normally | |
Read/Write |
Read Only or Protect |
Ends normally |
Depends on the attribute* | |
Read Only or Protect |
Read Only or Protect |
Depends on the attribute* |
Depends on the attribute* | |
Mirroring Suspended (when the I/O mode of the primary volume is Local and the I/O mode of the secondary volume is Block) |
Read/Write |
Read/Write |
Ends normally |
Rejected |
Read Only or Protect |
Read/Write |
Depends on the attribute* |
Rejected | |
Read/Write |
Read Only or Protect |
Ends normally |
Rejected | |
Read Only or Protect |
Read Only or Protect |
Depends on the attribute* |
Rejected | |
Suspended (when the I/O mode of the primary volume is Block and the I/O mode of the secondary volume is Local) |
Read/Write |
Read/Write |
Rejected |
Ends normally |
Read Only or Protect |
Read/Write |
Rejected |
Ends normally | |
Read/Write |
Read Only or Protect |
Rejected |
Depends on the attribute* | |
Read Only or Protect |
Read Only or Protect |
Rejected |
Depends on the attribute* | |
Block |
Read/Write |
Read/Write |
Rejected |
Rejected |
Read Only or Protect |
Read/Write |
Rejected |
Rejected | |
Read/Write |
Read Only or Protect |
Rejected |
Rejected | |
Read Only or Protect |
Read Only or Protect |
Rejected |
Rejected | |
* If the attribute is Read Only, Read is allowed but not Write. If the attribute is Protect, Read and Write are not allowed. |
Volume Migration (VSP G1x00 and VSP F1500)
You can use Volume Migration to move volumes in an overloaded drive to a non-overloaded drive online.
Volume Migration moves volumes by specifying the P-VOL and S-VOL of a GAD pair in an overloaded drive as the migration source volume which then moves the volumes to a non-overloaded drive.
Restrictions for using GAD with Volume Migration
There are restrictions of which you should be aware before you use Volume Migration to move a GAD pair volume.
- The GAD pair must be split before you specify the volumes as the migration source volumes for Volume Migration.
- Provisioning types of the GAD P-VOL and S-VOL must be the same. Ensure that the provisioning types of the GAD P-VOL and S-VOL are still the same after the migration by Volume Migration.
- When a GAD pair volume is shared by an SI pair volume, you cannot specify it as the source volume during Quick Restore of the SI pair. When Quick Restore completes, start using Volume Migration.
- For Volume Migration operation when using GAD with nondisruptive migration, see GAD status and nondisruptive migration pair operations.
GAD status and Volume Migration pair operations
The ability of Volume Migration to create or cancel migration plans depends on the status of the GAD pair.
The following table describes if you can create or cancel migration plans when GAD volumes are not mirrored.
GAD pair status |
Virtual LDEV ID |
I/O from the server |
Volume Migration operation | ||
Read |
Write |
Create migration plans |
Cancel migration plans | ||
SMPL |
Available |
Y |
Y |
Y |
Y |
Not available |
N |
N |
N |
Y | |
Not available (Virtual attribute: GAD reserve) |
N |
N |
N |
Y | |
Legend Y: Can be performed N: Cannot be performed |
The following table describes if you can create or cancel migration plans when GAD volumes are being mirrored.
GAD pair status |
I/O mode |
Pair location |
I/O from the server |
Volume Migration operation | ||
Read |
Write |
Create migration plans |
Cancel migration plans | |||
INIT/COPY |
Mirror(RL) |
Primary |
Y |
Y |
N |
Y |
Block |
Secondary |
N |
N |
N |
Y | |
Legend Y: Can be performed N: Cannot be performed |
The following table describes if you can create or cancel migration plans when GAD volumes are mirrored.
GAD pair status |
I/O mode |
Pair location |
I/O from the server |
Volume Migration operation | ||
Read |
Write |
Create migration plans |
Cancel migration plans | |||
PAIR |
Mirror(RL) |
Primary |
Y |
Y |
N |
Y |
Secondary |
Y |
Y |
N |
Y | ||
Legend Y: Can be performed N: Cannot be performed |
The following table describes if you can create or cancel migration plans when the GAD pair is suspended.
GAD pair status |
I/O mode |
Pair location |
I/O from the server |
Volume Migration operation | ||
Read |
Write |
Create migration plans |
Cancel migration plans | |||
PSUS/PSUE |
Local |
Primary |
Y |
Y |
Y |
Y |
Block |
Any |
N |
N |
Y |
Y | |
SSUS |
Block |
Secondary |
N |
N |
Y |
Y |
SSWS |
Local |
Secondary |
Y |
Y |
Y |
Y |
Legend Y: Can be performed N: Cannot be performed |
The following table describes if you can create or cancel migration plans when the GAD pair is blocked.
GAD pair status |
I/O mode |
Pair location |
I/O from the server |
Volume Migration operation | ||
Read |
Write |
Create migration plans |
Cancel migration plans | |||
PSUE |
Block |
Primary |
N |
N |
Y |
Y |
Secondary |
N |
N |
Y |
Y | ||
Legend Y: Can be performed N: Cannot be performed |
Volume Migration pair statuses and GAD pair operations (VSP G1x00 and VSP F1500)
You should understand what GAD operations you can perform given the Volume Migration pair status and whether the GAD P-VOL or S-VOL is shared by Volume Migration.
The following table describes operations you can perform according to the Volume Migration pair status when the GAD P-VOL is shared by Volume Migration.
Volume Migration pair status |
GAD pair operation | |||||||
Create |
Suspend |
Delete |
Resynchronize | |||||
P-VOL specified |
S-VOL specified |
P-VOL specified1 |
S-VOL specified2 |
Force delete |
P-VOL specified |
S-VOL specified | ||
SMPL(PD) |
No4 |
Yes |
Yes |
Yes |
No3 |
Yes |
No |
No |
COPY |
No4 |
Yes |
Yes |
Yes |
No3 |
Yes |
No |
No |
PSUS |
No4 |
Yes |
Yes |
Yes |
No3 |
Yes |
No |
No |
PSUE |
No4 |
Yes |
Yes |
Yes |
No3 |
Yes |
No |
No |
Note:
|
The following table describes operations you can perform according to the Volume Migration pair status when the GAD S-VOL is shared by Volume Migration.
Volume Migration pair status |
GAD pair operation | |||||||
Create |
Suspend |
Delete |
Resynchronize | |||||
P-VOL specified |
S-VOL specified |
P-VOL specified1 |
S-VOL specified2 |
Force delete |
P-VOL specified |
S-VOL specified | ||
SMPL(PD) |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
No |
No |
COPY |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
No |
No |
PSUS |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
No |
No |
PSUE |
No3 |
Yes |
Yes |
No4 |
Yes |
Yes |
No |
No |
Note:
|
LUN Manager
Use the volumes for which LU paths have been set to create a GAD pair. You can add LU paths to or delete LU paths from GAD pair volumes. However, you cannot delete the last LU path because at least one LU path must be set for GAD pair volumes.
A volume for which no LU path has been set cannot be used as a GAD pair volume.
When a port has a path defined for an LDEV with the GAD reserve attribute and you need to configure the port (delete a host group, set a command device, or change the host mode, topology, AL-PL, or transfer speed), the operation might fail if you configure more than one port at a time. For ports that have a path defined on an LDEV with the GAD reserve attribute, perform these operations on one port at a time.
Nondisruptive migration (VSP F1500 and VSP G1x00)
You can create a GAD pair using a volume being migrated by nondisruptive migration to migrate your data without changing system configuration, even if your system is designed for disaster recovery. The following figure shows an example of such data migration. For example, If you create a GAD pair using a volume being migrated while maintaining the configuration of the disaster recovery system using TrueCopy, you can maintain the disaster recovery system by GAD soon after migration.

For details, see the Nondisruptive Migration User Guide.
Restrictions for using GAD with nondisruptive migration
You should be aware of restrictions if you want to use GAD with nondisruptive migration.
- When creating a GAD pair, you cannot specify a volume being migrated by nondisruptive migration as its S-VOL.
- Before creating a GAD pair, you need to change the cache mode of the destination volume to Write Sync. Use CCI when changing the cache mode.
- I/O operations from the host to the GAD S-VOL cannot be performed until Volume Migration is completed. If you want to perform the operation which allows the host to recognize the GAD S-VOL, perform this operation after Volume Migration is completed.
- You cannot swap resynchronize GAD pairs. If you want to swap resynchronize them, delete Volume Migration pairs after Volume Migration ends.
- Before you start Volume Migration, set the same provisioning type for both the target volume of Volume Migration and the GAD S-VOL.
- 3-data-center (3DC) configurations using both GAD and Universal Replicator (UR) cannot be used for destination volumes. To use a 3DC configuration combining GAD and UR, configure the 3DC system after volumes are completely migrated by Volume Migration.
GAD status and nondisruptive migration pair operations
The following table shows the cache modes of nondisruptive migration and GAD pair operations.
Operation target |
Virtual LDEV ID |
GAD pair operation | |
P-VOL |
S-VOL | ||
Cache modes for external volume groups of the destination storage system |
TM (Cache Through) |
N |
N |
SM (Write Sync) |
Y |
N | |
Legend Y: Can be performed N: Cannot be performed |
The following table shows the possibility of GAD pair operation and cache mode change in nondisruptive migration.
Operation target |
Cache modes to which GAD P-VOL can be changed | ||
TM (Cache Through) |
SM |
EM/DM | |
GAD P-VOL |
N |
Y |
N |
Legend Y: Can be performed N: Cannot be performed |
The following table shows the possibility of Volume Migration pair operations (when a GAD pair operating with nondisruptive migration is in the initial status).
GAD pair status |
Virtual LDEV ID |
I/O from the server |
Volume Migration operation | ||
Read |
Write |
Migrate volumes |
Stop migrating volumes | ||
SMPL |
Specifed |
Y |
Y |
Y |
Y |
None |
N |
N |
N |
Y | |
None (GAD reserve is specified as the virtual attribute) |
N |
N |
N |
Y | |
Legend Y: Can be performed N: Cannot be performed |
The following table shows the possibility of Volume Migration pair operations (when a GAD pair operating with nondisruptive migration is being mirrored).
GAD pair status |
I/O mode |
Pair location |
I/O from the server |
Volume Migration operation | ||
Read |
Write |
Migrate volumes |
Stop migrating volumes | |||
INIT/COPY |
Mirror (RL) |
P-VOL |
Y |
Y |
N |
Y |
Block |
S-VOL |
N |
N |
N |
Y | |
Legend Y: Can be performed N: Cannot be performed |
The following table shows the possibility of Volume Migration pair operations (when a GAD pair operating with nondisruptive migration is already mirrored).
GAD pair status |
I/O mode |
Pair location |
I/O from the server |
Volume Migration operation | ||
Read |
Write |
Migrate volumes |
Stop migrating volumes | |||
PAIR |
Mirror (RL) |
P-VOL |
Y |
Y |
Y |
Y |
Block |
S-VOL |
N |
N |
N |
Y | |
Legend Y: Can be performed N: Cannot be performed |
The following table shows the possibility of Volume Migration pair operations (when a GAD pair operating with nondisruptive migration is suspended).
GAD pair status |
I/O mode |
Pair location |
I/O from the server |
Volume Migration operation | ||
Read |
Write |
Migrate volumes |
Stop migrating volumes | |||
PSUS/PSUE |
Local |
P-VOL |
Y |
Y |
Y |
Y |
Block |
Volume of your own choice (P-VOL or S-VOL) |
N |
N |
Y |
Y | |
SSUS |
Block |
S-VOL |
N |
N |
Y |
Y |
SSWS |
Local |
S-VOL |
Y |
Y |
Y |
Y |
Legend Y: Can be performed N: Cannot be performed |
The following table shows the possibility of Volume Migration pair operations (when a GAD pair operating with nondisruptive migration is blocked).
GAD pair status |
I/O mode |
Pair location |
I/O from the server |
Volume Migration operation | ||
Read |
Write |
Migrate volumes |
Stop migrating volumes | |||
PSUE |
Block |
P-VOL |
N |
N |
Y |
Y |
S-VOL |
N |
N |
Y |
Y | ||
Legend Y: Can be performed N: Cannot be performed |
The following table shows the GAD pair status in Volume Migration when GAD and nondisruptive migration are used together, and the possibility of Volume Migration pair operations (when the GAD P-VOL is a target volume of Volume Migration).
Volume Migration pair status |
Is VM P-VOL shared with NDM? |
Is VM S-VOL shared with NDM? |
GAD pair operation | ||||||||
Create |
Suspend |
Delete |
Resynchronize | ||||||||
P-VOL specified |
S-VOL specified |
P-VOL specified 1 |
S-VOL specified 2 |
Force delete |
P-VOL specified 3 |
S-VOL specified | |||||
SMPL (PD) |
Yes |
No4 |
Y |
Y |
Y |
Y |
N |
Y |
N |
N | |
COPY |
Yes |
No4 |
N |
Y |
Y |
Y |
N |
Y |
N |
N | |
PSUE |
Yes |
No4 |
N |
Y |
Y |
Y |
N |
Y |
N |
N | |
PSUS |
No4 |
Yes |
N |
Y |
Y |
Y |
N |
Y |
N |
N | |
Legend VM: Volume Migration NDM: nondisruptive migration Y: Can be performed N: Cannot be performed Note:
|
Volume Shredder
GAD pair volumes and quorum disks cannot use Volume Shredder to delete data.
Performance Monitor
Performance Monitor can be used to collect performance information about GAD pair volumes and the quorum disk.
The amount of a port's I/O that can be added to Performance Monitor depends on the type of the volume to which I/O is issued, or on the volume's I/O mode.
For example, when the I/O mode of both GAD volumes is Mirror (RL), each time the server writes to the P-VOL, performance data is recorded for all of the following ports and volumes:
- Primary storage system port connected to the host (Target)
- Primary storage system port connected to the secondary storage system (Initiator)
- Secondary storage system port connected to the primary storage system (RCU Target)
- P-VOL
- S-VOL
When the I/O mode of both GAD volumes is Mirror (RL), each time the server reads the P-VOL data, performance data is recorded for only the primary storage system host (Target) port and the P-VOL.
Server I/Os added to Performance Monitor
The number of I/Os (reads and writes) to GAD volumes that is added to Performance Monitor depends on the GAD status, as shown the following tables.
GAD status |
P-VOL |
S-VOL |
Mirrored |
The sum of the following values:
|
The sum of the following values:
|
Quorum disk blocked (status of GAD pairs created, resynchronized, or swap resynchronized on 80-04-2x or earlier for VSP G1x00 and VSP F1500 88-01-0x or later for VSP G350, G370, G700, G900 and VSP F350, F370, F700, F900) |
Number of writes to the P-VOL |
Number of RIOs to the S-VOL from the P-VOL |
Quorum disk blocked (status of GAD pairs created, resynchronized, or swap resynchronized on 80-05-0x or later for VSP G1x00 and VSP F150088-01-0x or later for VSP G350, G370, G700, G900 and VSP F350, F370, F700, F900) |
Number of writes to the P-VOL |
The sum of the following values:
|
Mirroring |
Number of writes to the P-VOL |
Number of RIOs to the S-VOL from the P-VOL |
Suspended (when the P-VOL has the latest information) |
Number of writes to the P-VOL |
Not counted* |
Suspended (when the S-VOL has the latest information) |
Not counted* |
Number of writes to the S-VOL |
Blocked |
Not counted* |
Not counted* |
* Reads and writes by a server are illegal requests and cause an error. However, they could be counted as I/O. |
GAD status |
P-VOL |
S-VOL |
Mirrored |
Number of reads from the P-VOL |
Number of reads from the S-VOL |
Quorum disk blocked (status of GAD pairs created, resynchronized, or swap resynchronized on 80-04-2x or earlier for VSP G1x00 and VSP F1500 ) |
Number of reads from the P-VOL |
Not counted* |
Quorum disk blocked(status of GAD pairs created, resynchronized, or swap resynchronized on 80-05-0x or later for VSP G1x00 and VSP F150088-01-0x or later for VSP G350, G370, G700, G900 and VSP F350, F370, F700, F900) |
Number of reads from the P-VOL |
Number of reads from the S-VOL |
Mirroring |
Number of reads from the P-VOL |
Not counted* |
Suspended (when the P-VOL has the latest information) |
Number of reads from the P-VOL |
Not counted* |
Suspended (when the S-VOL has the latest information) |
Not counted* |
Number of reads from the S-VOL |
Blocked |
Not counted* |
Not counted* |
* Reads and writes from a server are illegal requests and cause an error. However, they could be counted as I/O. |
GAD status |
Number of writes |
Number of reads |
Mirrored |
Approximately the same* as the number of writes to the P-VOL or S-VOL |
The same as the total number of reads from the P-VOL and S-VOL |
Quorum disk blocked (status of GAD pairs created, resynchronized, or swap resynchronized on 80-04-2x or earlier for VSP G1x00 and VSP F1500 ) |
The same as the number of writes to the P-VOL |
The same as the number of reads from the P-VOL |
Quorum disk blocked (status of GAD pairs created, resynchronized, or swap resynchronized on 80-05-0x or later for VSP G1000, VSP G1500, VSP F1500, 88-01-0x or later for VSP G350, G370, G700, G900 and VSP F350, F370, F700, F900) |
The same as the number of writes to the P-VOL |
The same as the total number of reads from the P-VOL and S-VOL |
Mirroring |
The same as the number of writes to the P-VOL |
The same as the number of reads from the P-VOL |
Suspended (P-VOL has latest data) |
The same as the number of writes to the P-VOL |
The same as the number of reads from the P-VOL |
Suspended (S-VOL has latest data) |
The same as the number of writes to the S-VOL |
The same as the number of reads from the S-VOL |
Blocked |
Not counted |
Not counted |
* For writes by a server, RIOs might be divided before being issued. For this reason, this number might differ from the number of writes by a server. |
Port I/Os added to Performance Monitor
The number of I/Os (reads or writes) of the port added to Performance Monitor depends on the P-VOL or S-VOL (I/O destination), or on the I/O mode of the destination volume, as shown in the following table.
I/O destination volume I/O mode | I/O destination volume | Primary storage system | Secondary storage system | ||||
Target | Initiator | RCU Target | Target | Initiator | RCU Target | ||
Mirror (RL) | P-VOL | Total writes and reads | Number of writes | Not added | Not added | Not added | Number of writes |
S-VOL | Not added | Not added | Number of writes | Total writes and reads | Number of writes | Not added | |
Local | P-VOL | Total writes and reads | Not added | Not added | Not added | Not added | Not added |
S-VOL | Not added | Not added | Not added | Total writes and reads | Not added | Not added | |
Block | P-VOL | Total writes and reads* | Not added | Not added | Not added | Not added | Not added |
S-VOL | Not added | Not added | Not added | Total writes and reads* | Not added | Not added | |
* Reads and writes by a server are illegal requests and cause an error. However, they might be counted as I/Os. |