Managing HP Serviceguard A.11.20.10 for Linux, December 2012

Figure 26 Physical Disks Combined into LUNs
NOTE: LUN definition is normally done using utility programs provided by the disk array
manufacturer. Since arrays vary considerably, you should refer to the documentation that
accompanies your storage unit.
For information about configuring multipathing, see “Multipath for Storage ” (page 78).
3.6.2 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 191).
3.6.3 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.
For a basic description of Linux LVM, see the article, Logical Volume Manager HOWTO on the
Linux Documentation Project page at http://www.tldp.org.
3.7 About Persistent Reservations
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).
3.7 About Persistent Reservations 69