Configuring clustering on a HP-UX host

This section describes how to configure a storage unit for clustering on a HP-UX host that uses the MC/ServiceGuard clustering software.

The steps to configure MC/ServiceGuard with the storage unit are the same as the steps in the Hewlett-Packard high availability documentation. You can find that documentation at http://www.docs.hp.com/en/ha.html.

After you configure your host for normal operating system access, the storage unit acts as a normal disk device in the MC/ServiceGuard configuration. You can create volume groups that contain the volumes by using the Hewlett-Packard logical volume manager. This method of disk management is more reliable, easier, and more flexible than whole-disk management techniques.

When you create volume groups, you can implement PV-Links, Hewlett-Packard's built-in multipathing software for high availability disks. You can also implement IBM Multipath Subsystem Device Driver (SDD), the IBM recommended multipathing software.

If you use the PV-Links multipathing software, complete the following steps:

Create the volume group, using the path to the volumes that you want as the primary path to the data.
Extend the volume group with the path to the volumes that are intended as alternate paths.
The logical volume manager reads the label on the disk and knows that it is an alternate path to one of the volumes in the group. The logical volume manager labels the volume.

As an example, assume that you have a host that has access to a volume on a storage unit with the device nodes c2t0d0 and c3t0d0. You can use the c2 path as the primary path and create the volume group that uses only the c2t0d0 path.
Extend the volume group to include the c3t0d0 path. When you issue a vgdisplay -v command on the volume group, the command lists c3t0d0 as an alternate link to the data.

If you use SDD, complete the following steps:

Create the volume group using the vpath devices, the alternate paths of the volume are controlled by the vpath.
Extend the volume group of another vpath device only for multivolume groups.
As the same example above, vpath1 controls two device nodes c2t0d0 and c3t0d0, you only need to create a volume group with vpath1 device.

With the SDD implementation, the utility vpcluster provides a convenient way for exporting and importing volume groups among the MC/Service Guards nodes.

Note: For more information about the SDD, see the IBM^® System Storage™ Multipath Subsystem Device Driver User's Guide at http://www-03.ibm.com/servers/storage/support/software/sdd.