Red Hat DEVICE-MAPPER MULTIPATH 4.6 Configuration And Administration Manual page 29

Attribute
getuid_callout
prio_callout
features
path_checker
rr_min_io
rr_weight
failback
Description
= all valid paths in 1 priority group
multibus
= 1 priority group per detected serial
group_by_serial
number
= 1 priority group per path priority value
group_by_prio
group_by_node_name
The default value is
failover
Specifies the default program and arguments to call out to
obtain a unique path identifier. An absolute path is required.
The default value is
/sbin/scsi_id -g -u -s
Specifies the the default program and arguments to call out to
obtain a path priority value. For example, the ALUA bits in
SPC-3 provide an exploitable prio value for example. "none"
is a valid value. The default value is no callout, indicating all
paths are equal
Specifies the default extra features of multipath devices. The
only existing feature is
is (null).
Specifies the default method used to determine the state of
the paths. Possible values include:
,
emc_clariion hp_sw
.
readsector0
Specifies the number of I/O requests to route to a path before
switching to the next path in the current path group. The
default value is 1000.
If set to , then instead of sending
priorities
requests to a path before calling
path, the number of requests to send is determined by
times the path's priority, as determined by the
rr_min_io
program. Currently, there are priority callouts
prio_callout
only for devices that use the
policy, which means that all the paths in a path group will
always have the same priority.
If set to , all path weights are equal. The default value
uniform
is .
uniform
Specifies path group failback.
A value of 0 or
immediate
path group whith a higher priority than the current path group
the system switches to that path group.
A numeric value greater than zero specifies deferred failback,
expressed in seconds.
Configuration File Defaults
= 1 priority group per target node name
.
. The default value
queue_if_no_path
readsector0
, and . The default value is
directio
to choose the next
selector
group_by_prio
specifies that as soon as there is a
.
, ,
tur
rr_min_io
path grouping
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