VERITAS Storage Foundation 4.1 Cross-Platform Data Sharing Administrator's Guide

Disk Group Tasks
24 VERITAS Storage Foundation CDS Administrator’s Guide
Disk Group Tasks
The following disk group tasks are supported:
◆ Changing the Alignment of a Disk Group by Encapsulation
◆ Object Alignment During Volume Creation
◆ Changing the Alignment of a Non-CDS Disk Group
◆ Determining the Setting of the CDS Attribute
◆ Joining Disk Groups
◆ Moving Objects Between CDS and Non-CDS Disk Groups
◆ Changing Default CDS Setting for Disk Group Creation
◆ Creating Non-CDS Disk Groups
◆ Upgrading an Older Version Non-CDS Disk Group
◆ Replacing a Disk in a CDS Disk Group
◆ Setting Device Quotas for CDS Disk Groups
Changing the Alignment of a Disk Group by Encapsulation
If you use the vxdiskadm command to encapsulate a disk into a disk group with an alignment of
8K, the disk group alignment must be reduced to 1. As part of the encapsulation process, you are
asked to confirm that this reduction of the disk group alignment is acceptable.
Note If you are using the vxencap command to perform the encapsulation, the alignment is
carried out automatically without a confirmation prompt.
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.