HP Serviceguard Extension for RAC (SGeRAC) manual Creating RAC Volume Groups on Disk Arrays

Logical volume “/dev/vg_rac/system.dbf” has been successfully created with character device “/dev/vg_rac/rsystem.dbf”

Logical volume “/dev/vg_rac/system.dbf” has been successfully extended

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.Set up the group directory for vg_rac:

#mkdir /dev/vg_rac

2.Create a control file named group in the directory /dev/vg_rac, as follows:

#mknod /dev/vg_rac/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

44 Serviceguard Configuration for Oracle 10g, 11gR1, or 11gR2 RAC