Red Hat ENTERPRISE LINUX 5 DM MULTIPATH Configuration And Administration Manual page 25

defaults {
user_friendly_names
path_grouping_policy
}
Table 4.1, "Multipath Configuration Defaults"
section of the multipath.conf configuration file. These values are used by DM-Multipath unless
they are overwritten by the attributes specified in the devices and multipaths sections of the
multipath.conf file.
Attribute
udev_dir
polling_interval
selector
path_grouping_policy
getuid_callout
prio_callout
path_checker
rr_min_io
max_fds
rr_weight
yes
multibus
describes the attributes that are set in the defaults
Description
Specifies the directory where udev device nodes are created. The
default value is /udev.
Specifies the interval between two path checks in seconds. The
default value is 5.
Specifies the default algorithm to use in determining what path to
use for the next I/O operation. The default value is round-robin
0.
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
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 method used to determine the state
of the paths. Possible values include: readsector0, tur,
emc_clariion, hp_sw, and directio. The default value is
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.
(RHEL 5.2 and later) Sets the maximum number of open file
descriptors for the multipathd process. In RHEL 5.3, this
option allows a value of max, which sets the number of open file
descriptors to the system maximum.
If set to priorities, then instead of sending rr_min_io
requests to a path before calling selector to choose the
Configuration File Defaults
15