Support of Oracle RAC ASM with SGeRAC, January 2008

HP Availability Clusters Solutions Lab 1/25/2008 Page 14

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. The example below demonstrates how volume group is created

using new DSF format. HP-UX will automatically use the redundant path for the volume group in the

background.

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

physical path for the first PV is /dev/rdisk/disk1 and the second PV is /dev/rdisk/disk2.

1. Create the volume group with the two PVs (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/rdisk/disk1

# pvcreate -f /dev/rdisk/disk2

# mkdir /dev/vgora_asm

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

# vgcreate /dev/vgora_asm /dev/disk/disk1

# vgextend /dev/vgora_asm /dev/disk/disk2

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 v3,

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.

# lvcreate -n lvol1 vgora_asm

# lvcreate -n lvol2 vgora_asm

# lvchange -C y /dev/vgora_asm/lvol1

# lvchange -C y /dev/vgora_asm/lvol2

# Assume vgdisplay shows each PV has 2900 extents in our example

# lvextend -l 2900 /dev/vgora_asm/lvol1 /dev/disk/disk1

# lvextend -l 2900 /dev/vgora_asm/lvol2 /dev/disk/disk2

# Assume a PV timeout of 30 seconds.

# There are 2 paths to each PV, so the LV timeout value is 60 seconds

# lvchange -t 60 /dev/vgora_asm/lvol1

# lvchange -t 60 /dev/vgora_asm/lvol2

# dd if=/dev/zero of=/dev/vgora_asm/rlvol1 bs=8192 count=12800