LVM Link and Node Failure Recovery Time (June 2009)

The number of shared volume groups in the cluster with at least one mirrored logical volume with

consistency recovery set to MWC or NOMWC.

HP-UX 11i v3 March 2008 release and prior HP-UX 11i releases

SLVM Recovery Time is the lesser of either:

• 570 seconds

• (Max PV timeout * 3) + (number of mirrored LVs) + 15 seconds

This formula is valid on the following HP-UX releases:

• All 11i v3 releases up to and including the March 2008 release

• All 11i v2 releases with LVM patch PHKL_34094 or superseding patch installed

• All 11i v1 releases with LVM patch PHKL_34093 or superseding patch installed

Example 1

An SGeRAC cluster has 6 shared volume groups each with 30 mirrored logical volumes and

consistency recovery set to NOMWC. The maximum PV timeout setting is 30 seconds.

SLVM Recovery Time = (30 seconds * 3) + (6 * 30) seconds + 15 seconds = 285 seconds

Note:

The minimum value for SLVM Recovery Time in the previous formula is 105 seconds. In practice, the

SLVM Recovery Time might be significantly less than 105 seconds, particularly if there were no

hardware failures.

HP-UX 11i v3 September 2009 release and later releases

SLVM Recovery Time is the lesser of either:

• 570 seconds

• (Max PV timeout * 3) + (number of shared VGs with mirrored LVs) +

15 seconds

Example 2

An SGeRAC cluster has 6 shared volume groups each with 30 mirrored logical volumes with

consistency recovery set to MWC. The maximum PV timeout setting is 30 seconds.

SLVM Recovery Time = (30 seconds * 3) + 6 seconds + 15 seconds = 111 seconds

Example 3

An SGeRAC cluster has 800 shared volume groups each with 10 mirrored logical volumes with

consistency recovery set to MWC. The maximum PV timeout setting is 30 seconds.

SLVM Recovery Time = (30 seconds * 3) + 800 seconds + 15 seconds = 905 seconds

Since 905 seconds is greater than 570 seconds, the SLVM Recovery Time is 570 seconds.

Note:

The minimum value for SLVM Recovery Time in the formula above is 105 seconds. In practice, the

SLVM Recovery Time might be less than 105 seconds, particularly if there were no hardware failures.