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

Moving disk groups between HP-UX and Linux systems

A disk group created on an HP-UX 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 an HP-UX 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.

Migrating a snapshot volume

This example demonstrates how to migrate a snapshot volume containing a VxFS

file system from a Solaris SPARC system (big endian) to a Linux system (little

endian) or HP-UX system (big endian) to a Linux system (little endian).

To migrate a snapshot volume

Create the instant snapshot volume, snapvol, from an existing plex in the

volume, vol, in the CDS disk group, datadg:

# vxsnap -g datadg make source=vol/newvol=snapvol/nmirror=1

Quiesce any applications that are accessing the volume. For example, suspend

updates to the volume that contains the database tables. The database may

have a hot backup mode that allows you to do this by temporarily suspending

writes to its tables.

61Transferring data between platforms

Moving disk groups between HP-UX and Linux systems