Red Hat ENTERPRISE LINUX 4 - DM MULTIPATH Manual page 29

Attribute
product
bl_product
path_grouping_policy
getuid_callout
prio_callout
path_checker
path_selector
failback
features
hardware_handler
rr_min_io
rr_weight
Description
Specifies the product name of the storage device to which the
device attributes apply, for example HSV110 (C)COMPAQ.
Specifies a regular expression used to blacklist devices by vendor/
product. Note that for a device to get blacklisted, the vendor,
product, and bl_product strings must all match.
Specifies the default path grouping policy to apply to unspecified
multipaths. Possible values include:
failover = 1 path per priority group
multibus = all valid paths in 1 priority group
group_by_serial = 1 priority group per detected serial number
group_by_prio = 1 priority group per path priority value
group_by_node_name = 1 priority group per target node name
Specifies the default program and arguments to call out to obtain a
unique path identifier. An absolute path is required.
Specifies the the default program and arguments to call out to
obtain a path weight. Weights are summed for each path group to
determine the next path group to use in case of failue. "none" is a
valid value.
Specifies the default method used to determine the state of
the paths. Possible values include readsector0 and tur,
emc_clariion, hp_sw, and directio.
Specifies the default algorithm to use in determining what path to
use for the next I/O operation.
Specifies path group failback.
A value of 0 or immediate specifies that as soon as there is a
path group with 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.
A value of manual specifies that failback can happen only with
operator intervention.
The extra features of multipath devices. The only existing
feature is queue_if_no_path, which is the same as setting
no_path_retry to queue.
Specifies a module that will be used to perform hardware specific
actions when switching path groups or handling I/O errors.
Possible values include 0, 1 emc, and 1 rdac. The default value
is 0.
(RHEL 4.8 and later) 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 priorities, then instead of sending rr_min_io
requests to a path before calling selector to choose the
next path, the number of requests to send is determined by
rr_min_io times the path's priority, as determined by the
prio_callout program. Currently, there are priority callouts only
Configuration File Devices
19