Hitachi Block Snapshot Configuration Wizard

Ops Center Protector User Guide
Version
7.7.x
Audience
anonymous
Part Number
MK-99PRT002-08
ft:lastEdition
2023-10-26

This dialog is displayed when you assign a snapshot operation to a node that hosts data stored on an Hitachi Block device.

CAUTION:
When a snapshot operation runs, Protector locks the meta_resource of the Block device until the operation completes. Block operations are queued waiting to get the resource lock; this can impact RPO.
Note:

All replication and snapshot S-VOLs must be created using free LDEV IDs that are mapped to the meta_resource group, and have virtual LDEV IDs matching their corresponding physical LDEV IDs.

For fully provisioned snapshots and all replications, this applies to the operation that creates that snapshot or replication.

For floating device snapshots and snapshots mounted using cascade mode, this applies to the mount or restore operation.

For fully provisioned snapshots mounted using cascade mode, this applies both to the operation that creates that snapshot and to the mount or restore operation.

If an operation tries to create one or more LDEVs, that operation will fail if there are not enough free LDEV IDs that meet the above conditions.

Note:
  • The classifications that are applicable to Hitachi Block Snapshot operations are Path, Application, Hypervisor and Hitachi Block.
  • Protector does not support any Hitachi Block storage LDEV with more than one partition or volume.
  • If Protector is subsequently uninstalled, the existing snapshots and mounted volumes are left in place.
Tip:
  • The actions that are performed by Protector as it executes a backup policy are captured by the Log Manager. Detailed logs and their attachments can be exported as a text file. (See Export Logs Dialog for more information.)
  • Details of the hardware resources (LDEVs) used for a particular snapshot can be found in the Hitachi Block Device Details.
Figure. Snapshot Configuration Wizard - Differential snapshot (using Thin Image)
Control Description
Storage Node Specifies the target storage node where the P-VOL and snapshot S-VOLs are allocated.
Snapshot Pool Specifies the target storage pool from one of the following options to which snapshot S-VOLs are allocated.
  • Match Source Pool – Allocates the snapshot in the same pool as the source volumes.
  • User Selected – Select a Thin Image Pool or a Dynamic Provisioning Pool.

Select a Thin Image Pool or a Dynamic Provisioning Pool.

CAUTION:

Filling a Thin Image pool to capacity will invalidate all snapshot data contained within that pool. All snapshots in the pool will have to be deleted before snapshotting can be resumed.

Note: Thin Image and Dynamic Provisioning Pools must be created using Storage Navigator prior to selecting the Target Storage in Protector.
Tip: If the P-VOL has an association with a VSM or you select a target storage pool associated with a VSM then Protector will attempt to make the virtual and the physical ID of the S-VOL holding the snapshot identical. For this to work, an LDEV with a physical ID within the defined virtual LDEV range for the selected VSM must available for use.
Advanced Configuration Click to step through the advanced configuration option pages of the wizard, described below.
Cancel Discards all changes and reverts to the previous page.
Previous Takes the user to the previous screen in the wizard.
Next Takes the user to the next screen in the wizard.
Figure. Snapshot Configuration Wizard - Configure Resource Group
Specifies the resource group to be used for S-VOLs, in order to support snapshots and replications from VSM volumes (adding volumes to a VSM is performed by adding the volumes to the correct resource group).
Control Description
Automatically Selected Allows Protector to automatically select a resource group in the following order of priority:
  1. If there are existing S-VOLs, then the resource group used by those will be selected.
  2. The resource group used by the P-VOLs, if the replication is in-system and the P-VOLs are all in one resource group.
  3. Resource group 0.
Note: If existing S-VOLs are in multiple resource groups, then the operation will fail with an error.
User Selected
Specify the Resource Group in the associated combo-box.
Note: If there are existing S-VOLs, then the resource group used by those will be selected. If the existing S-VOLs are in multiple resource groups or in a resource group that contradicts the user specification, then the operation will fail with an error.
Cancel Discards all changes and reverts to the previous page.
Previous Takes the user to the previous screen in the wizard.
Next Takes the user to the next screen in the wizard.
Figure. Snapshot Configuration Wizard - Provisioning Options
Specifies how the snapshot is provisioned and its mode of operation. Snapshots are created as differential, in-system snapshots using Thin Image.
CAUTION:
Block storage has a limit of 1024 snapshots per LDEV. Ensure that the RPO and Retention periods are set such that this limit is not exceeded (i.e. Retention / RPO is less than or equal to 1024).
Control Description
Consistency group When performing a crash consistent snapshot (for example: using the hardware path classification), use this option to make it truly crash consistent. The hardware has a limited number of consistency groups available so they should be used sparingly.
Fully Provisioned By default, this option is deselected and the snapshot will be provisioned using floating devices. Where supported by the array the storage device can store a larger number of snapshots using floating device.
Cascade Mode The snapshot can be cascaded. This allows Protector to mount either the original snapshot or a duplicate of the original. Mounting a duplicate enables modifications to be made without affecting the original snapshot.

Refer to About cascaded Thin Image and Thin Image Advanced snapshots for further guidance on configuring and mounting cascade mode snapshots.
Cascade Pool If Fully Provisioned is selected above, it may be necessary to specify a dynamic or hybrid pool where Protector can create snapshot S-VOLs.
Cancel Discards all changes and reverts to the previous page.
Previous Takes the user to the previous screen in the wizard.
Next Takes the user to the next screen in the wizard.
Figure. Snapshot Configuration Wizard - Naming Options
Specifies how secondary LDEVs and snapshot groups will be named.
Control Description
Secondary Logical Device Name Specifies how S-VOLs will be named:
  • Match Origin - The S-VOL will be given the same name as that used for the origin P-VOL (i.e. the left-most volume in the data flow).
  • Custom - The S-VOL will be named using the naming rule provided. The naming rule can consist of literal strings and/or one or more substitution variables listed. Click Display variables which can be used for the secondary LDEVs' name to view the available substitution variables:
    • %ORIGIN_SERIAL% - S/N of leftmost array in data flow. E.g. output string: 210613
    • %ORIGIN_LDEV_ID% - ID of leftmost LDEV in data flow. E.g. output string: 00:3A:98
    • %ORIGIN_LDEV_NAME% - name of leftmost LDEV in data flow.
    • %PRIMARY_SERIAL% - S/N of primary array in this operation. E.g. output string: 442302
    • %PRIMARY_LDEV_ID% - ID of primary LDEV in this operation. E.g. output string: 00:4C:EB
    • %PRIMARY_LDEV_NAME% - name of primary LDEV in this operation.
    • %SECONDARY_SERIAL% - S/N of secondary array in this operation. E.g. output string: 356323
    • %SECONDARY_LDEV_ID% - ID of secondary LDEV in this operation. E.g. output string: 01:F4:35
    • %CREATION_DATE% - date secondary LDEV was created by this operation. E.g. output string: 20180427
    • %CREATION_TIME% - time secondary LDEV was created by this operation. 1130
Snapshot Group Name Specifies how the snapshot group will be named when the Provisioning Options - Consistency group option is not selected.
  • Automatically Generated - The snapshot group name is generated by Protector based on the rules context ID and policy name.
  • Custom - The snapshot group is named using the string provided (limited to 28 characters). An '@' separator followed by a unique ID is then automatically appended to this name. The unique ID is composed of 3 base 36 characters and is required to enable Protector to manage the groups.
Cancel Discards all changes and reverts to the previous page.
Previous Takes the user to the previous screen in the wizard.
Next Takes the user to the next screen in the wizard.
Figure. Snapshot Configuration Wizard - DRU Options
If Fully Provisioned is selected on the Provisioning Options page on this wizard, these options are enabled to specify Data Retention Utility (DRU) protection parameters.
CAUTION:
Protector cannot mount a DRU protected snapshot. However a cascaded snapshot can be created and mounted if the original has Cascade mode enabled.
Control Description
Protection Type One of the following can be selected:
  • None - DRU protection is not applied the snapshot
  • Host Read Only (wtd) - Prevents hosts writing to the snapshot LDEV.
  • Full (wtd + svd) - As for wtd, plus the array is prevented from changing the contents of a snapshot LDEV using resync or restore. It also prevents deletion, mapping and unmapping of the snapshot from its LDEV.
Note: DRU can prevent mounting if the OS rejects a read-only volume (mount via cascade snapshot is unaffected, and therefore recommended).
Duration Of Settings Lock (Days)
CAUTION:
DRU protection cannot be removed while the lock is active.
Specify a duration in days during which the applied DRU protection cannot be removed. Once this duration has expired the protection is not automatically removed; it must be removed manually.
Cancel Discards all changes and reverts to the previous page.
Previous Takes the user to the previous screen in the wizard.
Next Takes the user to the next screen in the wizard.
Figure. Snapshot Configuration Wizard - Summary
Summarizes the configuration settings made by the user.