snapshot command creates instant plex-breakoff snapshots of all the volumes in the RVG at a single point in time.
The steps required to create plex-breakoff snapshots are as follows:
It is necessary to prepare the volumes under the RVG for the snapshot operation. For more information on preparing volumes, refer to Preparing the volumes.
You must create plexes for the required volumes before you take an instant plex breakoff snapshot.
vxsnap addmir command to add one or more plexes to a volume:
vxsnap -g diskgroup
[-b] addmir volume
Note Run this command on every data volume in the RVG that needs the plex-breakoff snapshot to be created.
For more information on creating the plexes, refer to the Veritas Volume Manager Administrator's Guide.
For more information on freezing or pausing the replication, refer to Freezing or pausing replication.
The instant plex-breakoff snapshot feature enables you to create plex-breakoff snapshots just like the traditional snapshot feature. This operation cannot be used for an RVG that consists of VxVM ISP volumes.
Prerequisites for creating instant plex breakoff snapshots
Make sure the volumes for which you want to create plex-breakoff snapshots already have the appropriate plexes created and are in an snapdone state.
Make sure you create the plexes using appropriate prefixes in case you want to use specific plexes for the snapshot operation.
If you do not specify the
plexprefix attribute when creating the plex-breakoff snapshots, a plex that is in the snapdone state gets selected, automatically.
To create a plex-breakoff snapshot of each data volume in an RVG, use the following command:
# vxrvg -g diskgroup [-P
snapshot command with its attributes to specify the type of snapshot that you want to create. This is the default if neither the
-S nor the
-F option is specified. By default, all the volumes will be included for instant plex breakoff snapshots, provided that they have the plex volumes appropriately created. To exclude any of the volumes, use one of the following attributes. Depending on the attribute specified with the
snapshot command, appropriate snapshots of the volumes are created.
exclude specifies a comma-separated list of volumes that do not need to be considered for any kind of snapshot.
plexprefix attribute specifies a prefix for the plexes that will be used for creating the plex-breakoff snapshots. This is allowed only if the
-S option is not specified or if you have specified a list of volumes for creating plex-breakoff volumes with the
vxrvg snapshot command.
This example describes the steps to create an instant plex breakoff snapshot for an RVG:
vxsnap -g hrdg prepare hr_dv01
vxsnap -g hrdg addmir hr_dv01
Repeat this step for all the required data volumes in the RVG. Initial synchronizing of the plexes may take some time depending on the size of the volume.
If you need to use specific plexes during the snapshot operation, make sure you name them appropriately when creating them. However, you can also do it later using the following command:
vxedit -g hrdg rename hr_dv01-02 snapplex-dv01
vxrvg -g hrdg -P JULY snapshot hr_rvg plexprefix=snapplex
Use the following command to create the snapshots without specifying the plex prefix:
vxrvg -g hrdg -P JULY1 snapshot hr_rvg
After taking a snapshot, unfreeze replication if you are using IBC messaging; otherwise, if you have paused replication, resume it. The snapshots are now ready for use.