Veritas Storage Foundation Cross-Platform Data Sharing 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

17Overview of CDS
Disk group alignment
Note: The map layout within a Data Change Object (DCO) volume changed with
the release of VxVM 4.0 to version 20. This can accommodate both FastResync
and DRL maps within the DCO volume. The original version 0 layout for DCO
volumes only accommodates FastResync maps.
Object alignment during volume creation
For CDS disk groups, VxVM objects that are used in volume creation are
automatically aligned to 8K. For non-CDS disk groups, the
vxassist attribute,
dgalign_checking, controls how the command handles attributes that are
subject to disk group alignment restrictions. If set to
strict, the volume length
and values of attributes must be integer multiples of the disk group alignment
value, or the command fails and an error message is displayed. If set to
round
(default), attribute values are rounded up as required. If this attribute is not
specified on the command-line or in a defaults file, the default value of
round is
used.
The diskalign and nodiskalign attributes of vxassist, which control whether
subdisks are aligned on cylinder boundaries, is honored only for non-CDS disk
groups whose alignment value is set to 1.