Novell LINUX ENTERPRISE SERVER 10 SP2 - STORAGE ADMINISTRATION GUIDE 05-15-2009 Administration Manual page 64

Multipath Attribute
rr_min_io
rr_weight
no_path_retry
failback
Configuring for Round-Robin Load Balancing
All paths are active. I/O is configured for some number of seconds or some number of I/O
transactions before moving to the next open path in the sequence.
Configuring for Single Path Failover
A single path with the highest priority (lowest value setting) is active for traffic. Other paths are
available for failover, but are not used unless failover occurs.
Grouping I/O Paths for Round-Robin Load Balancing
Multiple paths with the same priority fall into the active group. When all paths in that group fail, the
device fails over to the next highest priority group. All paths in the group share the traffic load in a
round-robin load balancing fashion.
64 SLES 10 SP2: Storage Administration Guide
Description
Specifies the number of I/O
transactions to route to a path
before switching to the next
path in the same path group,
as determined by the
specified algorithm in the
setting.
path_selector
Specifies the weighting
method to use for paths.
Specifies the behaviors to use
on path failure.
Specifies whether to monitor
the failed path recovery, and
indicates the timing for group
failback after failed paths
return to service.
When the failed path
recovers, the path is added
back into the multipath
enabled path list based on
this setting. Multipath
evaluates the priority groups,
and changes the active
priority group when the
priority of the primary path
exceeds the secondary
group.
Values
n (>0) Specify an integer value greater than 0.
1000 Default.
uniform Default. All paths have the same
round-robin weightings.
priorities Each path's weighting is determined
by the path's priority times the rr_min_io setting.
n (> 0) Specifies the number of retries until
stops the queuing and fails the path.
multipath
Specify an integer value greater than 0.
fail Specified immediate failure (no queuing).
queue Never stop queuing (queue forever until
the path comes alive).
immediate When a path recovers, enable the
path immediately.
n (> 0) When the path recovers, wait n seconds
before enabling the path. Specify an integer
value greater than 0.
manual (Default) The failed path is not
monitored for recovery. The administrator runs
the multipath command to update enabled
paths and priority groups.