Veritas Volume Manager 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

Online Relayout
40 VERITAS Volume Manager Administrator’s Guide
◆ Online relayout cannot transform sparse plexes, nor can it make any plex sparse. (A
sparse plex is not the same size as the volume, or has regions that are not mapped to
any subdisk.)
◆ The number of mirrors in a mirrored volume cannot be changed using relayout.
◆ Only one relayout may be applied to a volume at a time.
Transformation Characteristics
Transformation of data from one layout to another involves rearrangement of data in the
existing layout to the new layout. During the transformation, online relayout retains data
redundancy by mirroring any temporary space used. Read and write access to data is not
interrupted during the transformation.
Data is not corrupted if the system fails during a transformation. The transformation
continues after the system is restored and both read and write access are maintained.
You can reverse the layout transformation process at any time, but the data may not be
returned to the exact previous storage location. Any existing transformation in the volume
must be stopped before doing a reversal.
You can determine the transformation direction by using the vxrelayout status
volume command.
These transformations are protected against I/O failures if there is sufficient redundancy
and space to move the data.
Transformations and Volume Length
Some layout transformations can cause the volume length to increase or decrease. If either
of these conditions occurs, online relayout uses the vxresize(1M) command to shrink
or grow a file system as described in “Resizing a Volume” on page 245.