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4.4. Multipaths Device Configuration Attributes
Table 4.2, “Multipath Attributes” shows the attributes that you can set in the
multipaths
section of the multipath.conf
configuration file for each specific multipath device. These attributes apply only to the one specified multipath. These defaults are used by DM-Multipath and override attributes set in the defaults
and devices
sections of the multipath.conf
file.
Table 4.2. Multipath Attributes
Attribute | Description | ||||||
---|---|---|---|---|---|---|---|
wwid | Specifies the WWID of the multipath device to which the multipath attributes apply. | ||||||
alias | Specifies the symbolic name for the multipath device to which the multipath attributes apply. | ||||||
path_grouping_policy |
| ||||||
prio_callout | Specifies 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 failure. "none" is a valid value. | ||||||
path_selector | Specifies the default algorithm to use in determining what path to use for the next I/O operation. | ||||||
failback |
| ||||||
rr_weight |
| ||||||
no_path_retry |
| ||||||
user_friendly_names | If set to yes , specifies that the system should use the /etc/multipath/bindings file to assign a persistent and unique alias to the multipath, in the form of mpath n . If set to no , specifies that the system should use use the WWID as the alias for the multipath. In either case, what is specified here will be overridden by any device-specific aliases you specify with the alias attribute for a specific multipath device. | ||||||
flush_on_last_del | (Red Hat Enterprise Linux 5.3 and later) If set to yes , the multipathd daemon will disable queueing when the last path to a device has been deleted. | ||||||
rr_min_io | Specifies the number of I/O requests to route to a path before switching to the next path in the current path group. | ||||||
mode | (Red Hat Enterprise Linux 5.3 and later) The mode to use for the multipath device nodes, in octal. The default value is determined by the process. | ||||||
uid | (Red Hat Enterprise Linux 5.3 and later) The user ID to use for the multipath device nodes. You must use the numeric user ID. The default value is determined by the process. | ||||||
gid | (Red Hat Enterprise Linux 5.3 and later) The group ID to use for the multipath device nodes. You must use the numeric group ID. The default value is determined by the process. |
The following example shows multipath attributes specified in the configuration file for two specific multipath devices. The first device has a WWID of
3600508b4000156d70001200000b0000
and a symbolic name of yellow
.
The second multipath device in the example has a WWID of
1DEC_____321816758474
and a symbolic name of red
. In this example, the rr_weight
attributes is set to priorities
.
multipaths { multipath { wwid 3600508b4000156d70001200000b0000 alias yellow path_grouping_policy multibus path_selector "round-robin 0" failback manual rr_weight priorities no_path_retry 5 } multipath { wwid 1DEC_____321816758474 alias red rr_weight priorities } }