Creating schedules for synchronized snapshots

You can use the VSS Snapshot Scheduler wizard to add a snapshot schedule. The scheduling capability automates the process of refreshing snapshot sets simultaneously on the Primary and Secondary nodes. At the time that is scheduled for the snapshot, the snapshot volumes are automatically reattached, resynchronized, and then split again. Once configured and applied, a scheduler service VxSchedService.exe maintains the schedule.

If the Secondary host initially satisfies the required conditions but during execution of the synchronized snapshot operation some of the checks fail, then the command does not fail, but proceeds with creating the snapshots on the Primary host.

The wizard then logs an event with an appropriate error code, which can be viewed through the Event Viewer.

Note:

The VSS Snapshot Scheduler wizard does not prepare the snapshot mirror. Prepare the snapshot mirror on the Primary and Secondary hosts with the prepare command before running the VSS Snapshot Scheduler wizard.

To schedule a snapshot for a selected component

  1. From the VEA console URL bar, select the <host name> which is the system where the production volumes and snapshot mirrors are located, as the active host.
  2. In the tree view expand the system node, the Storage Agent node, and the VSS Writers node.
  3. Select one of the following depending on the application for which you want to create the snapshot:

    • For Exchange, right-click Microsoft Exchange Writer and click VSS Exchange Snapshot.

    • For SQL, right-click Microsoft SQL Writer and click VSS SQL Snapshot.

  4. In the Welcome panel, review the information and click Next.
  5. On the Select Component panel, specify the snapshot set parameters as follows and then click Next.

    Complete this panel as follows:

    Select component for snapshot operation

    Select the component for the snapshot set.

    To create snapshots for Exchange, select the appropriate storage group.

    To create snapshots for SQL, select the appropriate database.

    Snapshot set

    Enter a name for the snapshot set. The snapshot set metadata XML file is stored under this name, with the prefix "VM_".

    The XML file is stored by default in the directory that is shown on the screen.

    To change the XML file location, use a text editor to create a text file named redirect.txt. This text file should contain a single text line specifying the full path to the location of the XML file, for example, G:\BackupSets. Save the redirect.txt file in the default directory C:\Program Files\Veritas\Veritas Volume Manager\VSSXML.

    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

    • Only for Exchange, runs Eseutil to check for consistency before you truncate 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.

    For Exchange: optionally check Run Eseutil with the Copy option to check the snapshot for consistency.

    For SQL: Either type can be used to restore a database. However, if you want to replay logs in SQL Server as part of restoring a database, a Full backup needs to have been created earlier. When replaying logs, you can replay from the time of the last Full backup. A Copy backup does not affect this sequence of log replay and therefore is often used as an "out of band" copy for purposes such as testing or data mining.

  6. In the Change Attributes panel, optionally change the attributes for the snapshot volumes and click Next.

    Complete this panel as follows:

    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.

    The drive letters that are specified may not be available when the snapshot is taken. When this occurs, the snapshot operation is performed, but no drive letters are assigned.

    Plex

    Optionally, click a plex and select a new choice from the drop-down menu.

  7. On 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 are directly taken to the Schedule Information panel.

  8. In the Schedule Information panel, on the General Options tab, you need to the following.

    Complete the information as:

    Name of this schedule

    Enter a unique name for the snapshot set schedule. This name identifies the snapshot schedule if you later want to view information about the snapshot status. A default name consists of the VSS writer name, the component name, and a numbered suffix that increments with each schedule.

    Description of this schedule

    Optionally, enter a description to help you identify the schedule when you view information about the snapshot status.

    Start Time

    The time of the day to begin taking snapshots

    End Time

    The time of day to end taking snapshots.

    If a snapshot is in progress it is completed but a new one is not started after the end time.

    Schedule takes effect on

    The date on which the specified schedule takes effect. The default is the current date.

    Restart task every

    The interval between snapshots, in minutes.

    For example, if the interval is 360 minutes and you schedule a snapshot start time of 12:00 P.M. and an end time of 7:00 P.M., the snapshot occurs twice. If no interval is specified the snapshot occurs once.

    Every

    Enable the Every option to have the snapshot schedule continue to occur. Otherwise the schedule applies only for one day.

    Specify the number of days before restarting the snapshot schedule.

    For example, 1 day would mean that the schedule takes effect daily, 2 days would mean every other day.

    Start On

    If you enable the Every option, specify the starting date.

    Pre Command

    Optionally, specify the full path of a command script to run before the scheduled snapshot occurs.

    Post Command

    Optionally, specify the full path of a command script to run after the snapshot is complete.

  9. To specify additional schedule days or dates, make selections on the following tabs:

    Days of Week

    Select one or more days on one or more weeks of the month.

    You can click a button at the top of the column to select the entire column or a button to the left of a row to select the entire row. For example, clicking First schedules the snapshots to occur on the first occurrence of all the week days for the month.

    Days of Month

    Select one or more days of the month. You can also check the Last Day check box to schedule the snapshot for the last day of each month.

    Specific Dates

    Select one or more specific dates to include in or to exclude from the schedule.

    Excluding a date takes precedence over days scheduled on the other tabs. For example, if you schedule every Monday on the Days of Week tab, and you exclude Monday October 9 on the Specific Dates tab, the snapshots are not taken on October 9.

    If two schedules overlap for the same snapshot set, only one snapshot is taken. For example, if you select every Thursday plus the last day of the month, and the last day of the month occurs on Thursday, then only one snapshot is taken on Thursday.

  10. Click Next.
  11. Review the snapshot set and schedule details and click Finish.