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

Chapter 1, Overview

CDS Disk Access and Format

The size of the data written may not be an exact multiple of the block size used by the

accessing platform. Therefore the accessing platform cannot constrain its I/O within the

boundaries of the data on disk.

Operating System Data

Some Operating Systems (OS) require OS-specific data on disks in order to recognize and control

access to the disk.

CDS Disk Access and Format

For a disk to be accessible by multiple platforms, the disk must be consistently recognized by the

platforms, and all platforms must be capable of performing I/O on the disk. CDS disks contain

specific content at specific locations to identify or control access to the disk on different platforms.

The same content and location are used on all CDS disks, independent of the platform on which the

disks are initialized.

In order for a disk to be initialized as, or converted to a CDS disk, it must satisfy the following

requirements:

◆ Must be a SCSI disk that supports Mode Sense

◆ Cannot be an EFI disk

◆ Must be the entire physical disk (LUN)

◆ 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)

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 “Setting up Your System” on page 11 for more details.

Disk groups with version numbers less than 110 are not supported for the Solaris OS on the

X86 platform.