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

The Cross-Platform Data Sharing feature is also known as Portable Data Containers
(PDC). For consistency, this document uses the name Cross-Platform Data Sharing
throughout.
The following levels in the device hierarchy, from disk through file system, must
provide support for CDS to be used:
Application level.End-user applications
File system level.Veritas™ File System (VxFS)
Volume level.Veritas™ Volume Manager (VxVM)
Device level.Operating system
CDS is a license-enabled feature that is supported at the disk group level by VxVM
and at the file system level by VxFS.
CDS utilizes a new disk type (auto:cdsdisk). To effect data sharing, VxVM supports
a new disk group attribute (cds) and also supports different OS block sizes.
Note: CDS allows data volumes and their contents to be easily migrated between
heterogeneous systems. It does not enable concurrent access from different types
of platform unless such access is supported at all levels that are required.
Shared data across platforms
While volumes can be exported across platforms, the data on the volumes can be
shared only if data sharing is supported at the application level. That is, to make
data sharing across platforms possible, it must be supported throughout the entire
software stack.
For example, if a VxFS file system on a VxVM volume contains files comprising
a database, then the following functionality applies:
■ Disks can be recognized (as cds disks) across platforms.
■ Disk groups can be imported across platforms.
■ The file system can be mounted on different platforms.
However, it is very likely that, because of the inherent characteristics of databases,
you may not be able to start up and use the database on a platform different from
the one on which it was created. (A notable exception is Oracle 10g's Cross-Platform
Transportable Tablespace feature.)
An example is where an executable file, compiled on one platform, can be accessed
across platforms (using CDS), but may not be executable on a different platform.
Migrating data between platforms
Overview of CDS
456