Managing HP Serviceguard for Linux, Tenth Edition, September 2012

Monitoring Disks
Each package configuration includes information about the disks that are to be activated
by the package at startup. If monitoring is used, the health of the disks is checked at
package startup. The package will fail if the disks are not available.
When this happens, the package may be restarted on another node. If auto_run is set
to yes, the package will start up on another eligible node, if it meets all the requirements
for startup. If auto_run is set to no, then the package simply halts without starting up
anywhere else.
The process for configuring disk monitoring is described in “Creating a Disk Monitor
Configuration” (page 231).
More Information on LVM
Refer to the section “Creating the Logical Volume Infrastructure” in Chapter 5 for details
about configuring volume groups, logical volumes, and file systems for use in Serviceguard
packages.
Refer to the article, Logical Volume Manager HOWTO on the Linux Documentation Project
page at http://www.tldp.org for a basic description of Linux LVM.
About Persistent Reservations
As of A.11.19, Serviceguard for Linux packages use persistent reservations (PR) wherever
possible to control access to LUNs. Persistent Reservations, defined by the SCSI Primary
Commands version 3 (SPC-3) standard, provide a means to register I/O initiators and
specify who can access LUN devices (anyone, all registrants, only one registrant) and
how (read-only, write-only).
Unlike exclusive activation for volume groups, which does not prevent unauthorized
access to the underlying LUNs, PR controls access at the LUN level. Registration and
reservation information is stored on the device and enforced by its firmware; this
information persists across device resets and system reboots.
NOTE: Persistent Reservations coexist with, and are independent of, activation protection
of volume groups. You should continue to configure activation protection as instructed
under Enabling Volume Group Activation Protection. Subject to the Rules and Limitations
spelled out below, Persistent Reservations will be applied to the cluster's LUNs, whether
or not the LUNs are configured into volume groups.
About Persistent Reservations 83