Veritas Volume Manager 5.1 SP1 Administrator"s Guide (5900-1506, April 2011)

You can use volume conversion before or after you perform an online relayout to
achieve more transformations than would otherwise be possible. During relayout
process, a volume may also be converted into an intermediate layout. For example,
to convert a volume from a 4-column mirrored-stripe to a 5-column
mirrored-stripe, first use vxassist relayout to convert the volume to a 5-column
striped-mirror as follows:
# vxassist -g mydg relayout vol1 ncol=5
When the relayout finishes, use the vxassist convert command to change the
resulting layered striped-mirror volume to a non-layered mirrored-stripe:
# vxassist -g mydg convert vol1 layout=mirror-stripe
Note: If the system crashes during relayout or conversion, the process continues
when the system is rebooted. However, if the system crashes during the first stage
of a two-stage relayout and conversion, only the first stage finishes. To complete
the operation, you must run vxassist convert manually.
Adding a RAID-5 log
You can only have one RAID-5 plex per RAID-5 volume. Additional plexes become
RAID-5 log plexes, which log information about data and parity being written to
the volume. When you create a RAID-5 volume using the vxassist command, a
log plex is created for that volume by default.
To add a RAID-5 log to an existing volume, use the following command:
# vxassist [-b] [-g diskgroup] addlog volume [loglen=length]
If you specify the -b option, adding the new log is a background task.
When you add the first log to a volume, you can specify the log length. Any logs
that you add subsequently are configured with the same length as the existing
log.
For example, to create a log for the RAID-5 volume volraid, in the disk group
mydg, use the following command:
# vxassist -g mydg addlog volraid
Administering volumes
Adding a RAID-5 log
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