VERITAS Volume Manager 3.5 User's Guide - VERITAS Enterprise Administrator (September 2004)

Volume Tasks
Changing a Volume Layout
Chapter 4 127
• The Volume Change Layout task requires a volume name and a
different volume layout.
• Volumes remain accessible during online relayout.
• This task may take a long time, depending on the volume size and
other factors. The Relayout Status Monitor shows the progress of the
layout change and allows you to abort, pause, or reverse the task.
• If no disk space is specified, VxVM uses available space on disks in
the current disk group.
• If the temporary space size is not specified, VxVM uses an
appropriate size. Specifying a larger temporary space size speeds up
the layout change process because larger pieces of data are copied at
a time. If the specified temporary space size is too small, VxVM uses
a larger size.
• If all of the plexes in the volume have identical layouts, VxVM
changes all plexes (except log plexes) to the new layout. If the volume
contains plexes with different layouts, a target plex must be
specified. When a target plex is specified, VxVM changes the layout
of the target plex and leaves the other plexes in the volume alone.
• Log plex layouts do not change. VxVM removes and/or replaces log
plexes, depending on the new layout.
• If the volume length changes as a result of the layout change and the
volume contains a file system, the file system length is automatically
adjusted (if possible).
• A volume cannot undergo multiple relayouts at the same time.
• This task cannot be used to change the layout of a volume with a
sparse plex.
• This task may fail for volumes that were not created by VxVM or the
vxassist command.
• If the relayout is reversed, the volume returns to its original layout.
However, data in the volume may not return to its original storage
location.
• During a relayout, many other tasks are unavailable for the volume.
• A mirrored or striped volume requires at least two disks.
• A RAID-5 volume requires at least three disks.