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

Table 5-1
Commands for controlling the synchronization (continued)
DescriptionCommand
Start synchronization of a volume. The -b option
puts the operation in the background.
vxsnap [-b] [-gdiskgroup] syncstartvol
Stop synchronization of a volume.vxsnap [-g diskgroup] syncstop vol
Exit when synchronization of a volume is
complete. An error is returned if vol is invalid (for
example, it is a space-optimized snapshot), or if
vol is not being synchronized.
vxsnap [-g diskgroup] syncwait vol
The vxsnap snapwait command is provided to wait for newly linked break-off
snapshot volumes or volume sets to become ACTIVE, or for reattached snapshot
volumes to reach the SNAPDONE state following resynchronization.
See “Creating and managing linked break-off snapshot volumes” on page 114.
See “Reattaching a linked break-off snapshot volume” on page 119.
Improving the performance of snapshot synchronization
The following optional arguments to the -o option are provided to help optimize
the performance of synchronization when using the make, refresh, restore
and syncstart operations:
Specifies the size of each I/O request that is used when synchronizing
the regions of a volume. Specifying a larger size causes
synchronization to complete sooner, but with greater impact on the
performance of other processes that are accessing the volume. The
default size of 1m (1MB) is suggested as the minimum value for
high-performance array and controller hardware. The specified value
is rounded to a multiple of the volume’s region size.
iosize=size
Specifies the delay in milliseconds between synchronizing successive
sets of regions as specified by the value of iosize. This can be used
to change the impact of synchronization on system performance. The
default value of iodelay is 0 milliseconds (no delay). Increasing this
value slows down synchronization, and reduces the competition for
I/O bandwidth with other processes that may be accessing the volume.
slow=iodelay
Options may be combined as shown in the following examples:
125Administering instant snapshots
Creating instant snapshots