HP Serviceguard manual Using Mirrored Individual Data Disks, Creating Volume Groups

groups. For more information, see Using High Availability Monitors at the address given in the preface to this manual.

Using Mirrored Individual Data Disks

The procedures that follow use physical volume groups to allow mirroring of individual disks such that each logical volume is mirrored to a disk on a different I/O bus. This is known as PVG-strict mirroring.

Before you proceed, make sure your disk hardware is configured in such a way that a disk to be used as a mirror copy is connected to each node on a different bus from the bus that is used for the other (primary) copy.

Creating Volume Groups

NOTE: You can create volume groups by means of the cmpreparestg (1m) command. See “Using Easy Deployment Commands to Configure the Cluster” (page 162) for more information. If you use cmpreparestg, you can skip this step and proceed to “Making Physical Volume Group Files Consistent” (page 183).

Obtain a list of the disks on both nodes and identify which device files are used for the same disk on both. Use the following command on each node to list available disks as they are known to each system:

lssf /dev/d*/*

In the following examples, we use /dev/rdsk/c1t2d0 and /dev/rdsk/c0t2d0, which happen to be the device names for the same disks on both ftsys9 and ftsys10. In the event that the device file names are different on the different nodes, make a careful note of the correspondences.

NOTE: Under agile addressing, the physical devices in these examples would have names such as /dev/rdisk/disk1 and /dev/rdisk/disk2. See “About Device File Names (Device Special Files)” (page 80).

If you are using cDSFs, the device files would have names such as /dev/rcdisk/disk1 and /dev/rcdisk/disk2. See “About Cluster-wide Device Special Files (cDSFs)” (page 104).

On the configuration node (ftsys9), use the pvcreate(1m) command to define disks as physical volumes. This only needs to be done on the configuration node. Use the following commands to create two physical volumes for the sample configuration:

pvcreate -f /dev/rdsk/c1t2d0 pvcreate -f /dev/rdsk/c0t2d0

Use the following procedure to build a volume group on the configuration node (ftsys9). Later, you will create the same volume group on other nodes; see “Distributing Volume Groups to Other Nodes” (page 181).

NOTE: If you are using the March 2008 version or later of HP-UX 11i v3, you can skip steps 1 and 2; vgcreate (1m) will create the device file for you.

1.Create the group directory; for example, vgdatabase: mkdir /dev/vgdatabase

2.Create a control file named group in the directory /dev/vgdatabase, as follows: mknod /dev/vgdatabase/group c 64 0xhh0000

The major number is always 64, and the hexadecimal minor number has the form

0xhh0000

where hh must be unique to the volume group you are creating. Use a unique minor number that is available across all the nodes for the mknod command above. (This will avoid further reconfiguration later, when NFS-mounted logical volumes are created in the volume group.)

Preparing Your Systems 179