Veritas Storage Foundation 5.1 SP1 Advanced Features Administrator"s Guide (5900-1503, April 2011)

supported platform. A CDS disk group is composed only of CDS disks (VM disks
with the disk format cdsdisk), and is only available for disk group version 110
and greater.
Starting with disk group version 160, CDS disk groups can support disks of greater
than 1 TB.
Note: The CDS conversion utility, vxcdsconvert, is provided to convert non-CDS
VM disk formats to CDS disks, and disk groups with a version number less than
110 to disk groups that support CDS disks.
See “Converting non-CDS disks to CDS disks” on page 467.
All VxVM objects in a CDS disk group are aligned and sized so that any system
can access the object using its own representation of an I/O block. The CDS disk
group uses a platform-independent alignment value to support system block sizes
of up to 8K.
See “Disk group alignment” on page 461.
CDS disk groups can be used in the following ways:
■ Initialized on one system and then used “as-is” by VxVM on a system employing
a different type of platform.
■ Imported (in a serial fashion) by Linux, Solaris, AIX, and HP-UX systems.
■ Imported as private disk groups, or shared disk groups (by CVM).
You cannot include the following disks or volumes in a CDS disk group:
■ Volumes of usage type root and swap. You cannot use CDS to share boot devices.
■ Encapsulated disks.
Note: On Solaris and Linux systems, the process of disk encapsulation places the
slices or partitions on a disk (which may contain data or file systems) under VxVM
control. On AIX and HP-UX systems, LVM volumes may similarly be converted to
VxVM volumes.
Device quotas
Device quotas limit the number of objects in the disk group which create associated
device nodes in the file system. Device quotas are useful for disk groups which
need to be transferred between Linux with a pre-2.6 kernel and other supported
platforms. Prior to the 2.6 kernel, Linux supported only 256 minor devices per
major device.
Migrating data between platforms
CDS disk format and disk groups
460