How to snapshot a file system with Thin Image

Ops Center Protector User Guide

Version

7.7.x

Audience

anonymous

Part Number

MK-99PRT002-08

ft:lastEdition

2023-10-26

It is assumed that the following tasks have been performed:

The Protector Master software has been installed and licensed on a dedicated node. See Installation Tasks and License Tasks.
The Protector Client software has been installed on the source node where the Hitachi Block LDEV is mounted. Note that the LDEV is actually located on the Hitachi Block storage device.
The Protector Client software has been installed on the destination node that will act as a proxy for the Hitachi Block storage device. Note that for a Thin Image snapshot, the source and destination LDEVs are located on the same device.
The storage device has been set up as per the Protector requirements and prerequisites. Refer to Hitachi Block prerequisites.
Permissions have been granted to enable the Protector UI, required activities and participating nodes to be accessed. In this example all nodes will be left in the default resource group, so there is no need to allocate nodes to user defined resource groups. Refer to How to configure basic role based access control.

This task describes the steps to follow when protecting data that resides on a file system created on an LDEV allocated from a Hitachi Block storage device. Thin Image hardware snapshots of the P-VOL are created as S-VOLs residing within the same storage device. For more information, refer to About Thin Image and Thin Image Advanced differential and refreshed snapshots. The data flow and policy are as follows:

Figure. Hardware Snapshot Data Flow

Table. Path Snapshot Policy
Classification Type	Parameters	Value
Path	Include	E:\testdata (E: is where the Hitachi Block LDEV is mounted)

Operation Type	Parameters	Value	Assigned Nodes
Snapshot	Mode	Hardware	OS Host
	Hardware Type	Hitachi Block
	RPO	10 mins
	Retention	1 hour
	Run Options	Run on RPO

Locate the source node in the Nodes Inventory and check that it is authorized and online. This node is where the production LDEV to be snapshotted is mounted.
For a file system snapshot using a Path classification, a basic OS Host node is required. It is not necessary to create the source node in this case since all Protector client nodes default to this type when installed. See How to authorize a node.
Locate the node in the Nodes Inventory that will control the Hitachi Block Device via a CMD (Command Device) interface and check that it is authorized and online.
This node is used by Protector to orchestrate snapshot creation and is identified as the Proxy Node when creating the Hitachi Block Device node in the next step. This node is known as an ISM node. The ISM node does not appear in the data flow.
Create a new Hitachi Block Device node (unless one already exists) using the Hitachi Block Device Node Wizard and check that it is authorized and online.
The Hitachi Block Device node type is grouped under Storage in the Node Type Wizard. See How to add a node and How to authorize a node. Note that this node does not appear in the snapshot data flow diagram, but is identified when assigning the snapshot policy.
Define a policy as shown in the table above using the Policy Wizard, Path Classification Wizard and Snapshot Operation Wizard.
The Path classification is grouped under Physical classifications. See How to create a policy.
Draw a data flow as shown in the figure above, that shows only the OS Host source node, using the Data Flow Wizard.
At this stage the snapshot icon is not shown. See How to create a data flow.
Assign the Snapshot operation to the OS Host source node. The Path-Snapshot policy will then be assigned automatically.
See How to apply a policy to nodes on a data flow.

The Hitachi Block Snapshot Configuration Wizard is displayed.
Select the Snapshot Pool by selecting one of the available Thin Image or hybrid pools.

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.
Leave the remaining Advanced Options at their default settings, then click OK.
The snapshot icon is now shown superimposed over the source node.
Compile and activate the data flow, checking carefully that there are no errors or warnings.
See How to activate a data flow.
Locate the active data flow in the Monitor Inventory and open its Monitor Details page.
The policy will be invoked repeatedly according to the RPO specified. The policy can also be manually triggered from the source node in the monitor data flow. An initial snapshot will be taken shortly after rules distribution has completed. See How to trigger an operation from an active data flow.
Watch the active data flow via the Monitor Details to ensure the policy is operating as expected.
For a healthy data flow you will periodically see:
- Snapshot jobs appearing in the Jobs area below the data flow that cycle through stages and ending in Progress - Completed.
- Information messages appearing in the Logs area below the data flow indicating rules activation, storage handler and sequencer events.
- Attachments to storage handler log events confirming which volumes are being snapshotted.
For a problematic data flow you may see:
- Permanent Node Status icons appear over nodes and associated warning messages displayed to the right of the data flow area.
- Backup jobs appearing in the Jobs area below the data flow that cycle through stages and terminating in Progress - Failed.
- Warning and error messages appearing in the Logs area below the data flow indicating failed events.
Review the status of the Hitachi Block Device via the relevant Hitachi Block Device Details and snapshots via the Hitachi Block Snapshots Inventory, to ensure snapshots are being created.
Hitachi Block Devices require ongoing surveillance to ensure that they are operating correctly and sufficient resources are available to store your data securely. See How to view the status of a Hitachi Block storage device. The retention period of individual snapshots can be modified here if required.

New snapshots will appear in the Hitachi Block Snapshots Inventory periodically as dictated by the RPO of the policy. Old snapshots will be removed periodically as dictated by the Retention Period of the policy.