Veritas Storage Foundation Portable Data Containers: Cross-Platform Data Sharing 5.0.1 Administrators Guide, HP-UX 11i v3, First Edition, November 2009

■ Only one volume manager (such as VxVM) can manage a physical disk (LUN)

■ There can be no disk partition (slice) which is defined, but which is not

configured on the disk

■ Cannot contain a volume whose use-type is either root or swap (for example,

it cannot be a boot disk)

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 24.

Note: Disk groups with version numbers less than 110 are not supported for the

Solaris OS on the x64 platform.

CDS disk types

The CDS disk format, cdsdisk, is recognized by all VxVM platforms (including

Windows). The cdsdisk disk format is the default for all newly-created VM disks

unless overridden in a defaults file. The vxcdsconvert utility is provided to convert

other disk formats and types to CDS.

See “Defaults files” on page 28.

Note: Disks with format cdsdisk can only be added to disk groups with version

110 or later.

Private and public regions

A VM disk usually has a private and a public region.

The private region is a small area on the disk where VxVM configuration

information is stored, such as a disk header label, configuration records for VxVM

objects (such as volumes, plexes and subdisks), and an intent log for the

configuration database. The default private region size is 32MB, which is large

enough to record the details of several thousand VxVM objects in a disk group.

The public region covers the remainder of the disk, and is used for the allocation

of storage space to subdisks.

The private and public regions are aligned and sized in multiples of 8K to permit

the operation of CDS. The alignment of VxVM objects within the public region is

controlled by the disk group alignment attribute. The value of the disk group

alignment attribute must also be 8k to permit the operation of CDS.

Overview of CDS

CDS disk access and format