Using High Availability Monitors (June 2007)

Monitoring Disk Resources
Rules for Using the HA Disk Monitor with ServiceGuard
Chapter 240
configure PV links into separate PVGs, p in Table 2-7 will always be
equal to 1. Therefore any SCSI inquiry that does not return a value of UP
for every path will result in a calculation of DOWN for pv_summary.
Rules for RAID Arrays
RAID configurations must be configured with PV links. PV links are
redundant links attached to separate controllers on the array. If PV links
are configured, and one fails, LVM automatically switches to the
alternate controller when one fails.
To use the HA Disk Monitor with ServiceGuard, PV links must be
configured in separate PVG
S (physical volume groups). This new
requirement allows pv_summary to accurately calculate data availability
based on physical volume availability, thus including both ACTIVE and
INACTIVE volume groups.
If PV links are not configured in separate PVGs, the HA Disk Monitor
sees all links to the array as one physical volume. If one link fails,
pv_summary will register DOWN, and your package will fail over, even if
the other link is still up and data is available.
The following sections describe how to make sure your PV links are in
physical volume groups.
Adding PVGs to Existing Volume Groups
If you have already created volume groups, you can create PVGs and put
PV links into them.
1. Create a file called /etc/lvmpvg with permissions 600. See the
lvmpvg manpage and Managing Systems and Workgroups (HP Part
Number B2355-90664).
2. Create an entry for each volume group and assign a different PVG
name to each PV link. The PVG names can be any arbitrary name,
but must be unique on the system. For example, an array containing
2 volume groups, vgdance and vgsing, each containing a single LUN
and each with 2 PV links (see Figure 2-4 on page 51) should have the
following /etc/lvmpvg file:
VG /dev/vgdance
PVG busA
/dev/dsk/c1t0d0
/dev/dsk/c1t2d0