Creating a one-time snapshot set


Creating a one-time snapshot set
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Creating a one-time snapshot set is a two-step process as follows:

The first step is to prepare snapshot mirrors attached to all the original volumes in the specified database. If you are creating a snapshot set after a snapback to refresh existing snapshot mirrors, you can skip this step.

See Preparing the snapshot mirrors.
The second step uses either the vxsnap create command or the VSS Exchange Snapshot Wizard to create the snapshot set by detaching the snapshot mirrors from the original volumes. This step creates separate on-host snapshot volumes as well as an XML file to store the Exchange and snapshot volume metadata.

The vxsnap create command and VSS Exchange Snapshot Wizard integrate with VSS to quiesce the databases and then simultaneously snapshot the volumes in the database. This snapshot is done while the databases are online and without disrupting the email flow. The resulting snapshot set provides a complete picture of the database at the point in time the command is issued.

For Exchange 2010, if replication is enabled, you have the option to create a snapshot set of the passive copy instead of the active database. Additional information on the use of passive copy snapshots in a DAG is available.

See Exchange 2010 Database Availability Group (DAG) considerations.

The VSS Exchange Snapshot Wizard can be run from either a local system or a remote node. The vxsnap utility must be run from the local system.

Note that if your Exchange 2010 mailbox database is configured under a VCS cluster, then you can store the snapshot set metadata file in a file share path by configuring a file share resource. This is to avoid configuring extra shared volumes to store the snapshot set file, which is available once the mailbox database fails over.

You can also specify the file share path in place of the redirect.txt path, for example, \\MySystemName1\share1\QRDir. There can be a large number of mailbox databases in Exchange 2010 and each database may have independent schedules. Hence the number of different paths required for storing the snapshot metadata files is higher, which can be achieved by configuring a file share resource.

To create the snapshot set from the VEA console

From the VEA console, navigate to the system where the production volumes and snapshots mirrors are located.
Expand the system node, the Storage Agent node, and the Applications node.
Choose one of the following:
- Right-click Exchange and click VSS Exchange Snapshot.
- Optionally, if replication is enabled in an Exchange 2010 DAG and you want to create a snapshot on the replication node, right-click Exchange Replica and click VSS Exchange Snapshot.
In the wizard, review the Welcome page and click Next.

Specify the snapshot set parameters as follows and then click Next:

Select Component for snapshot operation

Select the component for the snapshot set.

For Exchange 2010, the component is a mailbox database.

Directory

Enter a directory location for the XML file or accept the default. The XML file is stored by default in the directory shown on the screen.

Note:

The XML file for the snapshot must be stored separately from the volumes that are included in the snapshots, otherwise a restore will fail.

In a clustered server environment, the XML file must be saved on shared storage to be available from all nodes in the cluster. To accomplish this, either edit the directory path in the Directory field for this wizard screen or use a text editor to create a text file named "redirect.txt." This text file should contain a single text line specifying the Universal Naming Convention (UNC) path to the location of the metadata file, for example, \\ServerName\SharedFolderName. Save the redirect.txt file in the default directory C:\Program Files\Veritas\Veritas Volume Manager\VSSXML on each node of the cluster.

Note:

You must not use the volume name or volume path in the redirect.txt file that is involved in the snapshot. If the volume name or path for the snapshot is used, then a restore will fail.

Snapshot set

Enter a name for the snapshot set. The snapshot set metadata XML file is stored under this name.

Select snapshot type

Select the snapshot type.

Full Backup is typically used for backup to tape or other storage media. It does the following:

Creates a copy of the selected component
Runs Eseutil to check for consistency before truncating the logs
Truncates the transaction logs

Copy is typically used for Quick Recovery. It creates a copy of the storage group, but does not truncate the transaction logs. Optionally check Run Eseutil with the Copy option to check the snapshot for consistency.

In the Change Attributes panel, optionally change the attributes for the snapshot volumes as follows and click Next:

Snapshot Volume Label	Displays the read-only label for the snapshot volume.
Drive Letter	Optionally, click a drive letter and select a new choice from the drop-down menu.
Plex	Optionally, click a plex and select a new choice from the drop-down menu.

Optionally, in the Synchronized Snapshot panel, select the secondary hosts for which you want to create synchronized snapshots. Either double-click on the host name or click the Add option to move the host into the Selected Secondary Hosts pane. To select all the available hosts, click the Add All option. The VSS wizard creates synchronized snapshots on all the selected secondary hosts.
This panel is displayed only in an environment using Volume Replicator. Otherwise, you will be directly taken to the Schedule Information panel.
Review the specifications of the snapshot set and click Finish.

To create the snapshot set from the command line

Type the command, as in the following example:

vxsnap -x snapdata.xml create writer="Microsoft Exchange Writer"
component=DB1 backupType=COPY -E -O

The complete syntax of the vxsnap create command is:

vxsnap [-x <filename>] create [source=<volume>]
   [/DriveLetter=<driveLetter>][/DrivePath=<drivePath>][/Newvol=<n
   ewVolName>][/Plex=<plexName>]...writer=<writerName>
   component=<componentName>[backuptype=<backuptype>][-E][-O][-C][
   secHosts=<secondary hosts>]

The WriterName and ComponentName must be included in the command. The option to assign drive letters or mount points is useful for tracking volumes and for scripting purposes. Creating the snapshot set with the copy backup type does not automatically run the Eseutil consistency check nor truncate the transaction logs. You can check the snapshot for consistency by specifying the -E flag.

Note:

Any text string that contains spaces must be enclosed in quotation marks.

See vxsnap create.

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