Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)
volume. If the volumes are in different disk groups, the command must be run
separately on each volume.
■ For full-sized instant snapshots, the vxsnap reattach operation is run to
return all of the plexes of the snapshot volume to the original volume.
■ For full-sized instant snapshots, the vxsnap dis or vxsnap split operations
are run on a volume to break the association between the original volume and
the snapshot volume. If the volumes are in different disk groups, the command
must be run separately on each volume.
Note: The vxsnap reattach, dis and split operations are not supported for
space-optimized instant snapshots.
For details about the snapshots and how to use them, see the Veritas Storage
Foundation Advanced Features Administrator's Guide.
See the vxassist(1M) manual page.
See the vxsnap(1M) manual page.
Effect of growing a volume on the FastResync map
It is possible to grow the replica volume, or the original volume, and still use
FastResync. According to the DCO volume layout, growing the volume has the
following different effects on the map that FastResync uses to track changes to
the original volume:
■ For a version 20 DCO volume, the size of the map is increased and the size of
the region that is tracked by each bit in the map stays the same.
■ For a version 0 DCO volume, the size of the map remains the same and the
region size is increased.
In either case, the part of the map that corresponds to the grown area of the
volume is marked as “dirty” so that this area is resynchronized. The snapback
operation fails if it attempts to create an incomplete snapshot plex. In such cases,
you must grow the replica volume, or the original volume, before invoking any of
the commands vxsnap reattach, vxsnap restore, or vxassist snapback.
Growing the two volumes separately can lead to a snapshot that shares physical
disks with another mirror in the volume. To prevent this, grow the volume after
the snapback command is complete.
FastResync limitations
The following limitations apply to FastResync:
Understanding Veritas Volume Manager
FastResync
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