Creating and deleting volumes
You can use the Device Manager - Storage Navigator software to create, edit, block, and delete the logical devices (LDEVs) on the storage system.
Create volumes for thick or thin provisioning according to SLA and other business requirements. Use the following information and instructions to configure thick volumes, or see About Dynamic Provisioning for information about thin provisioning.
RAID level support for CVs and pool-VOLs
The following table specifies the RAID level support for custom volumes (CVs) and pool volumes (pool-VOLs).
|
RAID level |
RAID configuration that can be applied to CV |
RAID configuration that can be applied to pool volume |
|
RAID 1 |
|
|
|
RAID 5 |
|
|
|
RAID 6 |
|
|
CV capacity
The following table defines the minimum capacity and maximum capacity for an OPEN-V volume (internal and external).
|
Emulation type* |
Minimum CV capacity |
Maximum CV capacity |
Number of control cylinders |
|
OPEN-V |
48,000 KB (96,000 blocks) |
|
None |
|
*If the parity group is 2D+1P or 4D+2P, the maximum CV capacity is 2 TB, which is 4,294,967,296 blocks. | |||
LDEV size calculations
When you create custom volumes (CVs), you can specify the capacity of each CV. However, rounding will produce different values for the user-specified CV capacity and the actual entire CV capacity. To calculate the actual capacity of a CV, you must use a mathematical formula. The following topics explain how to calculate the user area capacity and the entire capacity of a CV.
The entire capacity of a CV or an LDEV consists of two types of capacity. One type is the user area capacity that stores the user data. The second type is the capacity of all areas that are necessary for an LDEV implementation including control information. The sum of these two types of capacities is called the entire capacity.
Implemented LDEVs consume the entire capacity from the parity group capacity. Therefore, even if the sum of user areas of multiple CVs is the same as the user area of one CV, the remaining free space generated when multiple CVs are created can be smaller than the free space in the parity group when one CV is created.
When you create an LDEV, the actual capacity of the LDEV depends on whether you select the Capacity Compatibility Mode (Offset boundary) option on the Create LDEVs window. If the Capacity Compatibility Mode (Offset boundary) option is not selected, the LDEV is created with the specified capacity. If the Capacity Compatibility Mode (Offset boundary) option is selected, the specified LDEV capacity is offset by conforming to the prescribed boundary values, and an LDEV is created. The prescribed boundary value depends on the RAID level. For details about boundary values, see Boundary values of volumes.
- When to select the Capacity Compatibility Mode (Offset boundary) option In the storage system, data is managed based on a slot, and RAID data protection is performed based on a parity stripe unit. For an LDEV created with capacity offset by a boundary, the efficiency of the drive capacity is improved because the capacity of the LDEV is offset by the unit of the data management. Therefore, if there is an emphasis on the efficiency of the drive capacity, select the Capacity Compatibility Mode (Offset boundary) option when creating LDEVs.
- When NOT to select the Capacity Compatibility Mode (Offset boundary) option If you want the LDEV capacity to be a specific size, do not select the Capacity Compatibility Mode (Offset boundary) option when creating LDEVs. For example, if you want to create copy pairs with VSP, HUS VM, or other previous storage system models, you must use exactly the same LDEV capacity for the volumes in a pair.
Calculating OPEN-V volume size (CV capacity unit is MB)
The methods for calculating the user area capacity and the entire capacity of a CV vary depending on the CV capacity unit that is specified when creating the CV.
To calculate the user area capacity of a CV whose capacity unit is defined as megabytes:
ceiling(ceiling(user-specified-CV-capacity * 1024 / 64) / 15) * 64 * 15
where
- the value enclosed in
ceiling( )must be rounded up to the nearest whole number. - user-specified-CV-capacity is expressed in megabytes.
- The resulting user area capacity is expressed in kilobytes.
To calculate the entire capacity of a CV:
ceiling(user-area-capacity / boundary-value) * boundary-value / 1024
where
- the value enclosed in
ceiling( )must be rounded up to the nearest whole number. - user-area-capacity is expressed in kilobytes
- boundary value is expressed in kilobytes. The boundary value depends on the RAID level (see Boundary values of volumes).
- The resulting entire capacity is expressed in megabytes.
Calculating OPEN-V volume size (CV capacity unit is blocks)
To calculate the user area capacity of a CV whose capacity unit is defined as blocks:
ceiling(user-specified-CV-capacity / 2)
where
- the value enclosed in
ceiling( )must be rounded up to the nearest whole number. - user-specified-CV-capacity is expressed in blocks.
- The resulting user area capacity is expressed in kilobytes.
To calculate the entire capacity of a CV:
ceiling(user-specified-CV-capacity / (boundary-value * 2)) * (boundary-value * 2)
where
- the value enclosed in
ceiling( )must be rounded up to the nearest whole number. - user-specified-CV-capacity is expressed in blocks.
- boundary-value is expressed in kilobytes. The boundary value depends on the RAID level (see Boundary values of volumes).
- The resulting entire capacity is expressed in blocks. To convert the resulting entire capacity into megabytes, divide this capacity by 2,048.
Boundary values of volumes
The following table provides the boundary values (expressed as kilobytes) for internal volumes. The boundary value for an external volume is always one kilobyte, regardless of RAID level.
|
RAID level |
Boundary value (KB) | |
|
RAID 1 |
(2D+2D) |
1,024 |
|
RAID 5 |
(3D+1P) |
1,536 |
|
(4D+1P) |
2,048 | |
|
(6D+1P) |
3,072 | |
|
(7D+1P) |
3,584 | |
|
RAID 6 |
(6D+2P) |
3,072 |
|
(12D+2P) |
6,144 | |
|
(14D+2P) |
7,168 | |
Create LDEV function
Use the Create LDEV function to create a custom-size volume (CV).
The following diagram shows how custom-size volumes (CVs) are created. First you delete fixed-size volumes (FVs) to create free space, and then you can create one or more CVs of any size in that free space.
Finding an LDEV ID
When creating volumes, the LDEV ID (LDKC: CU: LDEV) must be specified. Use this procedure to determine the LDEV IDs in use in the storage system so you can specify the correct LDEV.
Procedure
Click Storage Systems, and then expand the Storage Systems tree.
Click Logical Devices.
In the LDEVs pane, click Create LDEVs.
In the Create LDEVs window, scroll down to Initial LDEV ID and click View LDEV IDs.
In the View LDEV IDs window, review the list to confirm the LDEV IDs. The LDEV IDs table shows the available, used, and disabled LDEV IDs.
The matrix vertical scale represents the second-to-last digit of the LDEV number, and the horizontal scale represents the last digit of the LDEV number.In the table, used LDEV numbers appear in blue, unavailable LDEV numbers appear in gray, and unused LDEV IDs appear in white. LDEV numbers that are unavailable may be already in use, or already assigned to another emulation group (group by 32 LDEV numbers).
Click Close.
Creating an LDEV
Use this procedure to create one or more internal or external logical volumes (also called LDEVs). You can create multiple LDEVs at once, for example, when you are setting up your storage system. After the storage system is set up, you can add LDEVs as needed.
Before you can create an LDEV in a storage system, you might need to create free space. Before deleting volumes to create free space, remove the LU paths to the volumes.
Before you begin
- The Storage Administrator (Provisioning) role is required to perform this task.
- You can create LDEVs using any of the following tabs in Hitachi Device Manager - Storage Navigator:
- Parity Groups tab when selecting Parity Groups.
You can create multiple LDEVs in the specified free space by setting the necessary items collectively. If multiple free spaces are in one parity group, the number of free spaces appears in Total Selected Free Space in the Parity Group Selection section on the Create LDEVs window. Confirm the number of free spaces, and then create the LDEVs accordingly.
For example, if you are creating LDEVs in parity group PG1-1 and it contains two free spaces, 2 appears in Total Selected Free Space. In this case, if you specify 1 in Number of LDEVs per Free Space, and continue to create the LDEV, two LDEVs are created because one LDEV is created for each free space.
When you select parity groups in the Parity Groups window or the Internal/External window, and open the Create LDEVs window, all free spaces in the parity groups are selected in the initial setting of the Select Free Spaces window. When you select the interleaved (concatenated) parity group in the Parity Groups window or the Internal/External window, and open the Create LDEVs window, all free spaces in every parity groups are selected in the initial setting of the Select Free Spaces window.
In this case, if LDEVs are created by the initial setting without confirming the number of free spaces, more LDEVs than necessary can be created. When you create LDEVs, confirm the number of free spaces displayed on the Select Free Spaces window in the Create LDEVs window
- LDEVs tab when selecting any parity group in Parity Groups.
- LDEVs tab when selecting Logical Devices.
- Parity Groups tab when selecting Parity Groups.
Procedure
In the Device Manager - Storage Navigator Explorer pane, click Storage Systems, expand the target storage system, and then click Logical Devices.
In the LDEVs tab, click Create LDEVs.
In the Create LDEVs window, from the Provisioning Type list, select the provisioning type for the LDEV to be created.
If you are creating an internal volume, select the parity group and free spaces to be assigned to the volume as follows:
In Parity Group Selection, select the desired Drive Type/RPM and RAID Level, and then click Select Free Spaces.
In the Select Free Spaces window, select the free spaces to be assigned to the volume.
Tip- To confirm where the selected free space is physically located, click View Physical Location.
- To apply filter conditions to the table, click Filter, specify the desired conditions, and then click Apply.
- To select all free spaces in the table, click Select All Pages. To cancel the selection, click Select All Pages again.
- To change the capacity unit or the number of rows to view, click Options.
In the Select Free Spaces window, if the selected free spaces have no issues, click OK.
If you are creating an external volume, select the free spaces to be assigned to the volume as follows:
In External Volume Selection, click Select Free Spaces.
In the Select Free Spaces window, select the free spaces to be assigned to the volume.
Tip- To confirm where the selected free space is physically located, click View Physical Location.
- To apply filter conditions to the table, click Filter, specify the desired conditions, and then click Apply.
- To select all free spaces in the table, click Select All Pages. To cancel the selection, click Select All Pages again.
- To change the capacity unit or the number of rows to view, click Options.
In the Select Free Spaces window, if the selected free spaces have no issues, click OK.
If you want to offset the specified LDEV capacity by boundary, set the Capacity Compatibility Mode (Offset boundary) to ON. Capacity Compatibility Mode (Offset boundary) is set to OFF by default.
In LDEV Capacity, type the amount of LDEV capacity to be created and select a capacity unit from the list.
Enter the capacity within the range of figures displayed below the text box. You can enter the number with 2 digits after decimal point. You can change the capacity unit from the list.In Number of LDEVs, type the number of LDEVs to be created.
- If you create internal volume, Number of LDEVs per Free Space appears.
- If you create external volume, Number of LDEVs per External Volume appears.
CautionIf creating LDEVs in the free space of the parity group with accelerated compression enabled, estimate the LDEV capacity and the number of LDEVs. For details, see GUID-E3D4AB72-202B-4969-AC7C-829F7EFDDB4A.
In LDEV Name, specify a name for this LDEV.
In Prefix, type the characters that will become the fixed characters for the beginning of the LDEV name. The characters are case-sensitive.
In Initial Number, type the initial number that will follow the prefix name.
In Format Type, select the desired format type for the LDEV.
- For an internal volume, select Normal Format, Quick Format, Parity Group Format, or No Format.
If you are creating an LDEV in a parity group with Accelerated Compression enabled, Quick Format cannot be selected.
If you select No Format, format the volume after creating the LDEV.
- For an external volume, select
Normal Format or
No Format.
If the external volume can be used as it is, select No Format. The created LDEV can be used without formatting.
If the external volume needs to be formatted, select No Format and then format the volume with the external storage system, or select Normal Format.
CautionIn some cases, Quick Format operations can affect host performance because shared resources such as MP units and cache paths are used during Quick Format. If you select Quick Format while Quick Format operations are already in progress, host I/Os might be affected. For details, see Quick Format function.- For an internal volume, select Normal Format, Quick Format, Parity Group Format, or No Format.
Click Options to show more options.
In Initial LDEV ID, make sure that an LDEV ID is set. To confirm the used number and unavailable number, click View LDEV IDs to open the View LDEV IDs window.
In Initial LDEV ID in the Create LDEVs window, click View LDEV IDs.
In the View LDEV IDs window, the matrix vertical scale represents the second-to-last digit of the LDEV number, and the horizontal scale represents the last digit of the LDEV number. The LDEV IDs table shows the available, used, and disabled LDEV IDs.In the table, used LDEV numbers appear in blue, unavailable numbers appear in gray, and unused numbers appear in white. LDEV numbers that are unavailable may be already in use, or already assigned to another emulation group (group by 32 LDEV numbers).
Click Close.
In the Create LDEVs window, from the MP Unit list, select a MP unit to be used by the LDEVs.
- If you assign a specific MP unit, select the ID of the MP unit.
- If you can assign any MP unit, click Auto.
In T10 PI, select Enable or Disable.
The T10 PI attribute can be specified when creating a Basic volume of emulation type OPEN-V.CautionThe T10 PI attribute can only be defined during the initial creation of LDEVs. The defined attribute cannot be removed from LDEVs on which it is already set.Click Add.
The LDEVs to be created are added to the Selected LDEVs table.The Provisioning Type, Parity Group Selection, LDEV Capacity, and Number of LDEVs per Free Space or Number of LDEVs per External Volume fields must be set. If these required items are not registered, you cannot click Add.
For the LDEVs in the Selected LDEVs table, you can change the following LDEV settings: LDEV name, initial LDEV ID, T10 PI, and MP unit.
If you need to delete an LDEV from the Selected LDEVs table, select the LDEV, and then click Remove.
When the information in the Selected LDEVs table is correct, click Finish.
The Confirm window appears.To continue the operation for setting the LU path and defining a logical unit, click Next.
In the Task Name text box, type a unique name for the task or accept the default.
You can enter up to 32 ASCII characters and symbols, with the exception of: \ / : , ; * ? " < > |. The value "date-window name" is entered by default.
Click Apply.
If Go to tasks window for status is selected, the Tasks window opens automatically.
Create LDEVs window
|
Item |
Description |
|
Provisioning Type |
Select the type of LDEV.
|
|
Data Direct Mapping |
Select Enable or Disable for the data direct mapping attribute. This item can be selected if the Provisioning Type is Dynamic Provisioning or External. If the Provisioning Type is External and an external volume with the data direct mapping attribute enabled does not exist, you cannot select Enable.
|
|
Capacity Saving |
Select the option for the capacity saving functions:
|
|
Multi-Tier Pool |
Select Enable or Disable if using Dynamic Tiering.
|
|
Active Flash |
Select to enable active flash. To select this item, all of the following conditions must be met:
|
|
Parity Group Selection, Pool Selection, or External Volume Selection |
Select the parity group to which the LDEV is assigned.
|
|
Drive Type/RPM |
Select the data drive type and RPM.
|
|
RAID Level |
Select the RAID level. When External Storage is selected from the Drive Type/RPM field, a hyphen (-) is displayed. |
|
Select Free Spaces |
Displays the Select Free Spaces window. |
|
Select Pool |
Displays the Select Pool window. |
|
Total Selected Free Spaces |
Displays the number of the selected free spaces. |
|
Total Selected Free Space Capacity |
Displays the total capacity of the free spaces. |
|
Selected Pool Name (ID) |
Displays the selected pool name and ID. |
|
Selected Pool Capacity |
Displays the selected pool capacity. |
|
LDEV Capacity |
Detailed calculation of the LDEV capacity differs depending on the specification of the unit. If the Data Direct Mapping is set to enable, this item is not displayed. (Open systems) When creating of LDEVs carved from accelerated compression-enabled parity groups, estimate the LDEV capacity. For details, see GUID-E3D4AB72-202B-4969-AC7C-829F7EFDDB4A. |
|
Number of LDEVs per Free Space, Number of LDEVs, or Number of LDEVs per External Volume |
Specify the number of LDEVs to create in a free space, pool, or the external volume. If the Provisioning Type is set to Dynamic Provisioning and the Data Direct Mapping is set to enable, this item is not displayed. If the Provisioning Type is set to External and the Data Direct Mapping is set to enable, 1 is displayed in the Number of LDEVs per External Volume. (Open systems) When creating LDEVs in accelerated compression-enabled parity groups, estimate the number of LDEVs. For details, see GUID-E3D4AB72-202B-4969-AC7C-829F7EFDDB4A. |
|
Available Volumes |
Select available volumes. This item is displayed when the Provisioning Type is Dynamic Provisioning and data direct mapping is enabled. The following items are displayed:
|
|
LDEV Name |
LDEV name. Specify the prefix characters and the initial number.
|
|
Format Type |
Specify the format type. This is displayed when an internal or external volume is used.
|
|
Initial LDEV ID |
Specify the LDEV ID. LDKC is fixed to 00. Default of CU and DEV is 00:00. For creating multiple LDEVs, select the interval of the assigned LDEV ID from the Interval list. |
|
View LDEV IDs |
Displays the View LDEV IDs windows. |
|
CLPR |
Cache logical partition number, displayed as ID:CLPR. |
|
MP Unit ID |
Specify the MP unit you want to assign to the LDEV. If automatic assignment is enabled for one or more MPs, you can also select Auto. If Auto is enabled, the default is Auto. If Auto is disabled, the default is the lowest number of the MP unit. |
|
Full Allocation |
Select Enable to reserve pages in a pool that is associated with LDEVs.
You can select Enable only when all of the following conditions are satisfied:
|
|
Tiering Policy |
Tiering Policy: All(0) is selected by default. You can change a level from Level1(1) to Level5(5) or from Level6(6) to Level31(31). See Notes on tiering policy settings. From Level 6 (6) to Level 31 (31), the names of tiering policies can also be changed. If these names have changed, the new names appear. You can specify this function when the multi-tier pool option is enabled. |
|
New Page Assignment Tier |
Specify the new page assignment tier you want to assign to the LDEV. Middle is selected by default. You can select from the levels of High, Middle, and Low. See New page assignment tier.You can specify this function when the multi-tier pool option is enabled. |
|
Relocation Priority |
Specify this option if the LDEV is to be relocated preferentially. You can select Default or Prioritize. You can specify this function when the Multi-Tier Pool is enabled. |
|
T10 PI |
Specify the LDEV's T10 PI attribute (Enabled or Disabled). This item can be specified only when the Provisioning Type is Basic, Dynamic Provisioning, or Snapshot. |
|
Add |
Adds the LDEVs that have settings specified in the setting field to the Selected LDEVs table. |
The items that can be set in this window depend on the type of volume you are creating. The following table lists the items that can be set according to volume type.
|
Item |
Internal volume |
V-VOL |
External volume |
Snapshot volume |
LDEV of the ALU attribution |
|
Provisioning Type |
Required |
Required |
Required |
Required |
N/A |
|
Data Direct Mapping |
N/A |
Optional |
Optional |
N/A |
N/A |
|
Capacity Saving |
N/A |
Optional |
N/A |
N/A |
N/A |
|
Multi-Tier Pool |
N/A |
Required |
N/A |
N/A |
N/A |
|
Active Flash |
N/A |
Optional |
N/A |
N/A |
N/A |
|
Drive Type/RPM |
Required |
Required |
Disabled |
N/A |
N/A |
|
RAID Level |
Required |
Required |
Disabled |
N/A |
N/A |
|
Select Free Spaces |
Required |
N/A |
Required |
N/A |
N/A |
|
Select Pool |
N/A |
Required |
N/A |
N/A |
N/A |
|
Capacity Compatibility Mode (Offset boundary) |
Optional |
Optional |
Optional |
Optional |
N/A |
|
LDEV Capacity |
Required |
Required |
Required |
Required |
N/A |
|
Number of LDEVs per Free Space |
Required |
N/A |
N/A |
N/A |
N/A |
|
Number of LDEVs |
N/A |
Required |
N/A |
Required |
Required |
|
Number of LDEVs per External Volume |
N/A |
N/A |
Required |
N/A |
N/A |
|
Available Volumes |
N/A |
Optional |
Optional |
N/A |
N/A |
|
LDEV Name |
Optional |
Optional |
Optional |
Optional |
Optional |
|
Format Type |
Required |
N/A |
Required |
N/A |
N/A |
|
Initial LDEV ID |
Optional |
Optional |
Optional |
Optional |
Optional |
|
View LDEV IDs |
Optional |
Optional |
Optional |
Optional |
Optional |
|
CLPR |
N/A |
Optional |
N/A |
Optional |
Optional |
|
MP Unit ID |
Optional |
Optional |
Optional |
Optional |
Optional |
|
Full Allocation |
N/A |
Optional |
N/A |
N/A |
N/A |
|
Tiering Policy |
N/A |
Optional |
N/A |
N/A |
N/A |
|
New Page Assignment Tier |
N/A |
Optional |
N/A |
N/A |
N/A |
|
Relocation Priority |
N/A |
Optional |
N/A |
N/A |
N/A |
|
T10 PI |
Optional |
Optional |
N/A |
Optional |
N/A |
|
Item |
Description |
|
LDEV ID |
LDEV identifier, which is the combination of LDKC, CU, and LDEV. |
|
LDEV Name |
LDEV name, including the combination of prefix characters and the initial number. |
|
Parity Group ID |
Parity group identifier. |
|
Pool Name (ID) |
Pool name and pool identifier. |
|
Data Direct Mapping |
Information about the data direct mapping.
|
|
Drive Type/RPM |
Drive type and rpm in use on this LDEV. |
|
RAID Level |
RAID level. An asterisk "*" indicates that the parity group to which the LDEV belongs is interleaved (concatenated). |
|
Capacity |
LDEV capacity. |
|
Format Type |
Format type. |
|
CLPR |
Cache logical partition number, displayed as ID:CLPR. For detailed information about CLPRs, see the Performance Guide. |
|
MP Unit ID |
MP unit identifier. If Auto is selected, the ID is automatically assigned. |
|
Multi-Tier Pool |
Indicates whether Dynamic Tiering is enabled or disabled.
|
|
Full Allocation |
Displays the status of the setting for the full allocation in a pool associated with the V-VOL.
|
|
Active Flash |
Indicates whether active flash is enabled or disabled. Enabled: The LDEV is for active flash . Disable: The LDEV is for Dynamic Tiering . - (hyphen): The LDEV is for Dynamic Provisioning . |
|
Tiering Policy |
The tiering policy name and ID for the LDEV. |
|
New Page Assignment Tier |
Displays the new page assignment tier for the LDEV. |
|
Relocation Priority |
Displays the relocation priority assigned to the LDEV. |
|
Capacity Saving |
Displays the capacity saving setting:
|
|
Attribute |
Displays the attribute of the LDEV.
|
|
Encryption |
Encryption information:
|
|
Accelerated Compression |
Displays information about the accelerated compression of the parity group that is created of LDEVs Enabled: The accelerated compression of the parity group is enabled. Disabled: The accelerated compression of the parity group is disabled. - (hyphen): The parity group with accelerated compression is not supported. |
|
T10 PI |
Displays the LDEV's T10 PI attribute information (Enabled or Disabled). |
|
Resource Group Name (ID) |
Resource group name and ID of which this LDEV is a member. |
|
Virtual Storage Machine |
Displays the information about the virtual storage machine.
|
|
Change LDEV Settings |
Opens the Change LDEV Settings window. |
|
Remove |
Removes the added LDEV. |
Deleting an LDEV (converting to free space)
You can convert one or more of the LDEVs on a selected parity group into free space by deleting the LDEVs. That free space can be used to either create one or more variable-sized volumes (CVs) using the Create LDEVs function, or left as free space for future use.
An LDEV cannot be deleted successfully if it is:
- In the defined path (including the pair volumes of TrueCopy, global-active device, and Universal Replicator).
- A pool-VOL.
- A journal volume.
- A remote command device.
- A volume security volume.
- A quorum disk used by global-active device.
- An LDEV that has the Read/Write access attribute.
When you delete an LDEV, the alias information contained in the LDEV is also deleted. Therefore, if you delete an LDEV related to an alias device, you should do one of the following:
- Allocate another LDEV to the alias device, and then delete the LDEV.
- Delete the LDEV first, and then allocate another LDEV to the alias device.
For information about how to delete a registered external volume, see the Hitachi Universal Volume Manager User Guide.
Before you begin
- The Storage Administrator (Provisioning) role is required to perform this task.
- Back up your data before deleting LDEVs.
Procedure
Click Storage Systems, and then expand the Storage Systems tree.
Click Logical Devices.
Select the LDEV ID of the LDEV you want to delete.
Click More Actions and select Delete LDEVs.
The LDEV is deleted.Note the settings in the Confirm window and enter a unique Task Name or accept the default, and then click Apply.
If Go to tasks window for status is checked, the Tasks window opens.