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.


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.