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

that mirroring is PVG-strict—it occurs between different physical volume groups; the -n
system.dbf option lets you specify the name of the logical volume; and the -L 408 option
allocates 408 megabytes.
Example for “MWC”:
# lvcreate -m 1 -M y -s g -n system.dbf -L 408 /dev/vg_ops
The -M y option ensures that mirror write cache recovery is set ON.
NOTE: Contact Oracle to determine if your version of Oracle RAC allows “resilvering” and to
appropriately configure the mirror consistency recovery policy for your logical volumes.
In the case Oracle “resilvering” is available, create logical volumes for use as Oracle data files
by using the same options as in the following example:
# lvcreate -m 1 -M n -c n -s g -n system.dbf -L 408 /dev/vg_ops
The -m 1 option specifies single mirroring; the -M n option ensures that mirror write cache
recovery is set off; the -c n means that mirror consistency recovery is disabled; the -s g means
that mirroring is PVG-strict—it occurs between different physical volume groups; the -n
system.dbfoption lets you specify the name of the logical volume; and the -L 408 option
allocates 408 megabytes.
If the command is successful, the system will display messages like the following:
Logical volume “/dev/vg_ops/system.dbf” has been successfully created
with character device “/dev/vg_ops/rsystem.dbf”
Logical volume “/dev/vg_ops/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 */
Assuming the disk array has been configured, and both of the following device files appear for
the same LUN (logical disk) when you run the ioscan command:
Creating a Storage Infrastructure with LVM 79