Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010 Administration Manual page 63

Multipath Attribute Description
path_grouping_policy Specifies the path grouping
policy for a multipath device
hosted by a given controller.
path_checker Determines the state of the
path.
Values
failover: One path is assigned per priority group
so that only one path at a time is used.
multibus: (Default) All valid paths are in one
priority group. Traffic is load-balanced across all
active paths in the group.
group_by_prio: One priority group exists for
each path priority value. Paths with the same
priority are in the same priority group. Priorities
are assigned by an external program.
group_by_serial: Paths are grouped by the
SCSI target serial number (controller node
WWN).
group_by_node_name: One priority group is
assigned per target node name. Target node
names are fetched in
/sys/class/
fc_transport/target*/node_name
directio: (Default in multipath-tools
0.4.8 and later) Reads the first sector that has
direct I/O. This is useful for DASD devices. Logs
failure messages in /var/log/messages
readsector0: (Default in
multipath-tools
version 0.4.7 and earlier) Reads the first sector
of the device. Logs failure messages in
.
log/messages
tur: Issues a SCSI test unit ready command to
the device. This is the preferred setting if the
LUN supports it. The command does not fill up
on failure with messages.
var/log/messages
Some SAN vendors provide custom
path_checker options:
emc_clariion: Queries the EMC Clariion
EVPD page 0xC0 to determine the path
state.
hp_sw: Checks the path state (Up, Down,
or Ghost) for HP storage arrays with Active/
Standby firmware.
rdac: Checks the path state for the LSI/
Engenio RDAC storage controller.
Managing Multipath I/O for Devices
.
version
.
/var/
/
63