Novell LINUX ENTERPRISE SERVER 10 SP3 - STORAGE ADMINISTRATION GUIDE 2-23-2010 Administration Manual page 62

Multipath Attribute
path_grouping_policy
path_checker
path_selector
pg_timeout
62 SLES 10 SP3: Storage Administration Guide
Description
Specifies the path grouping
policy for a multipath device
hosted by a given controller.
Determines the state of the
path.
Specifies the path-selector
algorithm to use for load-
balancing.
Specifies path group timeout
handling.
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:
Queries the EMC Clariion
emc_clariion
EVPD page 0xC0 to determine the path
state.
Checks the path state (Up, Down, or
hp_sw
Ghost) for HP storage arrays with Active/
Standby firmware.
rdac Checks the path state for the LSI/
Engenio RDAC storage controller.
round-robin 0 (Default) The load-balancing
algorithm used to balance traffic across all active
paths in a priority group.
This is currently the only algorithm available.
NONE (internal default)
.
version
.
/var/
/