Support of Oracle RAC ASM with SGeRAC, January 2008

HP Availability Clusters Solutions Lab 1/25/2008 Page 9

The SLVM volume groups are marked as shared volume groups and exported across the SGeRAC

cluster using standard SGeRAC procedures. As noted above, multiple physical paths to each physical

volume should be configured using the LVM PV Links feature or a separate multipathing product such

as HP StorageWorks Secure Path.

Please note that, for the case in which the SLVM PVs being used by ASM are disk array LUs, the

requirements in this section do not place any constraints on the configuration of the LUs. The LUs may

be configured with striping, mirroring and other characteristics at the array level, following guidelines

provided by Oracle and the array provider for use by ASM.

Sample Command Sequence for Configuring SLVM Volume Groups

In this section, we provide an example of a command sequence that can be used to prepare SLVM

Logical Volumes for use by ASM to meet the requirements specified above.

The scenario for our example is that we are preparing a new volume group named vgora_asm with

two PVs, each with two physical paths. The physical paths for the first PV are /dev/dsk/c9t0d1 and

/dev/dsk/c10t0d1 and those for the second PV are /dev/dsk/c9t0d2 and /dev/dsk/c10t0d2.

1. Create the volume group with the two PVs, incorporating the two physical paths for each

(choosing hh to be the next hexadecimal number that is available on the system, after the volume

groups that are already configured) :

# pvcreate -f /dev/dsk/c9t0d1

# pvcreate -f /dev/dsk/c9t0d2

# mkdir /dev/vgora_asm

# mknod /dev/vgora_asm/group c 64 0xhh0000

# vgcreate /dev/vgora_asm /dev/dsk/c9t0d1

# vgextend /dev/vgora_asm /dev/dsk/c9t0d2

# vgextend /dev/vgora_asm /dev/dsk/c10t0d1

# vgextend /dev/vgora_asm /dev/dsk/c10t0d2

2. For each of the two PVs, create a corresponding LV

• Create an LV of zero length

• Mark the LV as contiguous

• Extend each LV to the maximum size possible on that PV (the number of extents available in

a PV can be determined via vgdisplay -v <vgname>)

• Configure LV timeouts, based on the PV timeout and number of physical paths, as

described in the previous section. If a PV timeout has been explicitly set, its value can be

displayed via pvdisplay -v. If not, pvdisplay will show a value of default, indicating that the

timeout is determined by the underlying disk driver. For SCSI, in HP-UX 11i v2, the default

timeout is 30 seconds.

• Null out the initial part of each LV to ensure ASM accepts the LV as an ASM disk group

member.

Note that we are zeroing out the LV data area, not its metadata. It is the ASM

metadata that is being cleared.

See Oracle Metalink Doc ID: Note:268481.1 RE-CREATING ASM INSTANCES AND DISKGROUPS at https://metalink.oracle.com/ (Oracle

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