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

HP-UX, importing a shared disk group will result in the volumes being active and

enabled for shared-write. In the case of HP-UX, the shared volumes will be inactive

and require other actions to activate them for shared-write operations.

Disk group alignment and encapsulated disks

On the Solaris OS, all native file systems are cylinder aligned. Encapsulating such

a disk results in subdisks that are also cylinder aligned. Such alignment will

normally not be 8K aligned, but it will be 1K aligned. For the encapsulation process,

there is no flexibility as to where on the disk the subdisks must be since the data

location is predefined. If an alignment conflict occurs, user intervention is required.

If the disk group alignment is 8K this operation will probably fail because this

would require the cylinder to be an even number of 8K blocks in size.

Disk group import between Linux and non-Linux

machines

A disk group created on a non-Linux system typically has device numbers greater

than 1000. When that disk group is imported on a Linux machine with a pre-2.6

kernel, the devices are reassigned minor numbers less than 256.

If a disk group on a Linux system is imported to a non-Linux system, all device

numbers will be less than 256. If those devices are available (that is, they do not

conflict with devices in an imported boot disk group) they will be used. Otherwise

new device numbers will be reassigned.

A single disk group could contain a number of devices exceeding the maximum

number of devices for a given platform. In this case, the disk group cannot be

imported on that platform because import would exhaust available minor devices

for the VxVM driver. Although the case of minor number exhaustion is possible

in a homogeneous environment, it will be more pronounced between platforms

with different values for the maximum number of devices supported, such as

Linux with a pre-2.6 kernel. This difference will render platforms with low

maximum devices supported values less useful as heterogeneous disk group

failover or recovery candidates.

Note: Using the disk group maxdev attribute may reduce the likelihood that a CDS

disk group import on Linux with a per-2.6 kernel will exceed the maximum number

of devices.

Transferring data between platforms

Disk group alignment and encapsulated disks