Managing HP Serviceguard for Linux, Tenth Edition, September 2012

NOTE: Multipath capabilities are supported by FibreChannel HBA device drivers and
the Linux Device Mapper. Check with the storage device documentation for details.
See also “Multipath for Storage ”.
You can use the worksheet to record the names of the device files that correspond to
each LUN for the Fibre-Channel-attached storage unit.
Multipath for Storage
The method for achieving a multipath solution is dependent on the storage sub-system
attached to the cluster and the Host Bus Adapters (HBAs) in the servers. Please check the
documentation that accompanied your storage sub-system and HBA.
For fibre-channel-attached storage, the multipath function within the HBA driver should
be used, if it is supported by HP. For the QLogic driver, see “Using the QLogic HBA
driver for single-path or multipath failover mode on Linux systems application note”,
which you can find by entering the terms qlogic multipath application into the
search box of www.hp.com.
NOTE: With the rapid evolution of Linux, the multipath mechanisms may change, or
new ones may be added. Serviceguard for Linux supports DeviceMapper multipath
(DM-MPIO) with some restrictions; see the Serviceguard for Linux Certification Matrix at
the address provided in the Preface to this manual for up-to-date information.
NOTE: md also supports software RAID; but this configuration is not currently supported
with Serviceguard for Linux.
Disk I/O Information
You may want to use the Hardware worksheet in Appendix C to record the following
information for each disk connected to each disk device adapter on the node:
Bus Type Indicate the type of bus. Supported buses are SAS (Serial
Attached SCSI) and FibreChannel.
LUN Number Indicate the number of the LUN as defined in the storage unit.
Slot Number Indicate the slot number(s) into which the SCSI or FibreChannel
interface card(s) are inserted in the backplane of the computer.
Address Enter the bus hardware path number, which is the numeric
part of the host parameter, which can be seen on the system
by using the following command:
cat /proc/scsi/scsi
Disk Device File Enter the disk device file name for each SCSI disk or LUN.
94 Planning and Documenting an HA Cluster