Veritas Storage Foundation Intelligent Storage Provisioning 5.0.1 Administrators Guide, HP-UX 11i v3, First Edition, November 2009

Creating and managing full-sized instant snapshots
Full-sized instant snapshots are not suitable for write-intensive volumes (such
as for database redo logs) because the copy-on-write mechanism may degrade the
performance of the volume.
If you intend to split the volume and snapshot into separate disk groups (for
example, to perform off-host processing), you must use a fully synchronized linked
break-off snapshot. You cannot use a full-sized instant snapshot for this purpose
with ISP volumes.
For full-sized instant snapshots, you must prepare a volume that is to be used as
the snapshot volume. This must be the same size as the volume for which the
snapshot is being created, and it must also have the same region size.
See Creating a volume for use as a full-sized instant or linked break-off snapshot
on page 100.
The attributes for a snapshot are specified as a tuple to the vxsnap make command.
This command accepts multiple tuples; one for each snapshot that is being created.
Each element of a tuple is separated from the next by a slash character (/). Tuples
are separated by white space.
To create and manage a full-sized instant snapshot
1
Prepare an existing volume, snapvol, that is to be used as the snapshot volume.
See Creating a volume for use as a full-sized instant or linked break-off
snapshot on page 100.
2
To create a full-sized instant snapshot, snapvol, use the following forms of
the vxsnap make command:
# vxsnap [-g diskgroup] make source=volume/snapvol=snapvol\
[/syncing=off]
Background synchronization of the snapshot volume from its parent volume
is enabled by default (equivalent to specifying the syncing=on attribute). If
you do not want to move the snapshot into a separate disk group, or turn it
into an independent volume, specify the syncing=off attribute to disable
synchronization. This avoids unnecessary system overhead.
For example, to use the prepared volume, snap1myvol, as the snapshot for
the volume, myvol, in the disk group, mydg, use the following command:
# vxsnap -g mydg make source=myvol/snapvol=snap1myvol
If you want to turn a snapshot into an independent volume, you must wait
for its contents to be synchronized with those of its parent volume.
Administering instant snapshots
Creating instant snapshots
112