Veritas Storage Foundation Cross-Platform Data Sharing 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

54 Transferring data between platforms
Moving disk groups between HP-UX and Linux systems
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 an HP-UX system (big endian) to a Linux system (little
endian).
To migrate a snapshot volume
1 On the HP-UX system, 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
2 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.
3 Refresh the plexes of the snapshot volume using the following command: