Using Serviceguard Extension for RAC, 9th Edition, September 2010

NOTE: The character device file name (also called the raw logical volume name) is used by the
Oracle DBA in building the OPS database.
Creating RAC Volume Groups on Disk Arrays
The procedure described in this section assumes that you are using RAID-protected disk arrays
and LVM’s physical volume links (PV links) to define redundant data paths from each node in
the cluster to every logical unit on the array.
On your disk arrays, you should use redundant I/O channels from each node, connecting them
to separate controllers on the array. Then you can define alternate links to the LUNs or logical
disks you have defined on the array. If you are using SAM, choose the type of disk array you
wish to configure, and follow the menus to define alternate links. If you are using LVM commands,
specify the links on the command line.
The following example shows how to configure alternate links using LVM commands. 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 procedure to configure a volume group for this logical disk:
1. First, set up the group directory for vg_ops:
# mkdir /dev/vg_ops
2. Next, create a control file named group in the directory /dev/vg_ops, as follows:
# mknod /dev/vg_ops/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 the next hexadecimal
number that is available on your system, after the volume groups that are already configured.
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 -f /dev/rdsk/c0t15d0
It is only necessary to do this with one of the device file names for the LUN. The -f option
is only necessary if the physical volume was previously used in some other volume group.
4. Use the following to create the volume group with the two links:
# vgcreate /dev/vg_ops /dev/dsk/c0t15d0 /dev/dsk/c1t3d0
46 Serviceguard Configuration for Oracle 10g, 11gR1, or 11gR2 RAC