Red Hat DEVICE-MAPPER MULTIPATH 4.6, Configuration And Administration Manual

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out, as follows.
#defaults {
# udev_dir /dev
# polling_interval 10
# selector "round-robin 0"
# path_grouping_policy multibus
# getuid_callout "/sbin/scsi_id -g -u -s /block/%n"
# prio_callout /bin/true
# path_checker readsector0
# rr_min_io 100
# rr_weight priorities
# failback immediate
# no_path_retry fail
# user_friendly_name yes
#}
To overwrite the default value for any of the configuration parameters, you can copy the
relevant line from this template into the
defaults
section and uncomment it. For example, to
overwrite the
path_grouping_policy
parameter so that it is
multibus
rather than the default
value of
failover
, copy the appropriate line from the template to the initial
defaults
section of
the configuration file, and uncomment it, as follows.
defaults {
user_friendly_names yes
path_grouping_policy multibus
}
Table 4.1, “Multipath Configuration Defaults” describes the attributes that are set in the
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 Description
udev_dir
Specifies the directory where
udev
device nodes are created.
The default value is
/udev
.
polling_interval
Specifies the interval between two path checks in seconds.
The default value is 5.
selector
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
.
path_grouping_policy
Specifies the default path grouping policy to apply to
unspecified multipaths. Possible values include:
failover
= 1 path per priority group
Chapter 4. The DM-Multipath Configuration File
18