Using EMS HA Monitors

44 Chapter 2

Monitoring Disk Resources

Rules for Using the EMS Disk Monitor with MC/ServiceGuard

type of disk array you wish to conﬁgure, and follow the menus to deﬁne alternate

links. Be sure to specify a different physical volume group for each link to the same

disk.

The following example shows how to conﬁgure alternate links using LVM

commands. In the example, the following disk conﬁguration is assumed:

8/0.15.0 /dev/dsk/c0t15d0 /* I/O Channel 0 (8/0) SCSI address 15 LUN 0 */

8/0.15.1 /dev/dsk/c0t15d1 /* I/O Channel 0 (8/0) SCSI address 15 LUN 1 */

8/0.15.2 /dev/dsk/c0t15d2 /* I/O Channel 0 (8/0) SCSI address 15 LUN 2 */

8/0.15.3 /dev/dsk/c0t15d3 /* I/O Channel 0 (8/0) SCSI address 15 LUN 3 */

8/0.15.4 /dev/dsk/c0t15d4 /* I/O Channel 0 (8/0) SCSI address 15 LUN 4 */

8/0.15.5 /dev/dsk/c0t15d5 /* I/O Channel 0 (8/0) SCSI address 15 LUN 5 */

10/0.3.0 /dev/dsk/c1t3d0 /* I/O Channel 1 (10/0) SCSI address 3 LUN 0 */

10/0.3.1 /dev/dsk/c1t3d1 /* I/O Channel 1 (10/0) SCSI address 3 LUN 1 */

10/0.3.2 /dev/dsk/c1t3d2 /* I/O Channel 1 (10/0) SCSI address 3 LUN 2 */

10/0.3.3 /dev/dsk/c1t3d3 /* I/O Channel 1 (10/0) SCSI address 3 LUN 3 */

10/0.3.4 /dev/dsk/c1t3d4 /* I/O Channel 1 (10/0) SCSI address 3 LUN 4 */

10/0.3.5 /dev/dsk/c1t3d5 /* I/O Channel 1 (10/0) SCSI address 3 LUN 5 */

Assume that the disk array has been conﬁgured, and that both the following device

ﬁles appear for the same LUN (logical disk) when you run the ioscan command:

/dev/dsk/c0t15d0

/dev/dsk/c1t3d0

Use the following steps to conﬁgure a volume group for this logical disk:

1. First, set up the group directory for vgdatabase:

# mkdir /dev/vgdatabase

2. Next, 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 an

appropriate hexadecimal number that is available on your system, after the

volume groups that are already conﬁgured. On a single system, this might be the

next hexadecimal number, on a cluster, these number must be assigned

cluster-wide, so it should be one of the hexadecimal numbers used in the cluster.

Use the following command to display a list of existing volume groups:

# ls -l /dev/*/group

3. Use the pvcreate command on one of the device ﬁles associated with the

LUN to deﬁne the LUN to LVM as a physical volume.

# pvcreate /dev/dsk/c0t15d0

It is only necessary to do this with one of the device ﬁle names for the LUN.