1 .TH MULTIPATH.CONF 5 "30 November 2006"
3 multipath.conf \- multipath daemon configuration file
6 is the configuration file for the multipath daemon. It is used to
7 overwrite the built-in configuration table of \fBmultipathd\fP.
8 Any line whose first non-white-space character is a '#' is considered
9 a comment line. Empty lines are ignored.
11 The configuration file contains entries of the form:
35 Each \fIsection\fP contains one or more attributes or subsections. The
36 recognized keywords for attributes or subsections depend on the
37 section in which they occor.
39 The following \fIsection\fP keywords are recognized:
42 This section defines default values for attributes which are used
43 whenever no specific setting is given.
46 This section defines which devices should be excluded from the
47 multipath topology discovery.
49 .B blacklist_exceptions
50 This section defines which devices should be included in the
51 multipath topology discovery, despite being listed in the
56 This section defines the multipath topologies. They are indexed by a
57 \fIWorld Wide Identifier\fR(wwid), which is the result of the
58 \fIgetuid_callout\fR program.
61 This section defines the device-specific settings.
64 .SH "defaults section"
67 section recognizes the following keywords:
70 interval between two path checks in seconds For properly functioning paths,
71 the interval between checks will gradually increase to (4 * polling_interval);
76 directory where udev creates its device nodes; default is
80 default verbosity. Higher values increase the verbosity level. Valid
81 levels are between 0 and 6; default is
85 The default path selector algorithm to use; they are offered by the
86 kernel multipath target. The only currently implemented is
89 .B path_grouping_policy
90 The default path grouping policy to apply to unspecified
91 multipaths. Possible values are
95 1 path per priority group
98 all paths in 1 priority group
101 1 priority group per serial number
104 1 priority group per priority value. Priorities are determined by
105 callout programs specified as a global, per-controller or
106 per-multipath option in the configuration file.
108 .B group_by_node_name
109 1 priority group per target node name. Target node names are fetched
110 in /sys/class/fc_transport/target*/node_name.
112 Default value is \fImultibus\fR.
116 The default program and args to callout to obtain a unique path
117 identifier. Should be specified with an absolute path. Default value
119 .I /lib/udev/scsi_id --whitelisted --device=/dev/%n
122 The default program and args to callout to obtain a path priority
123 value. The specified program will be executed and should return a
124 numeric value specifying the relative priority of this path. Higher
125 number have a higher priority. A '%n' in the command line will be expanded
126 to the device name, a '%b' will be expanded to the device number in
130 is a valid value. Currently the following path priority programs are
134 .B mpath_prio_emc /dev/%n
135 Generate the path priority for EMC arrays
137 .B mpath_prio_alua /dev/%n
138 Generate the path priority based on the SCSI-3 ALUA settings.
140 .B mpath_prio_netapp /dev/%n
141 Generate the path priority for NetApp arrays.
143 .B mpath_prio_rdac /dev/%n
144 Generate the path priority for LSI/Engenio RDAC controller.
146 .B mpath_prio_hp_sw /dev/%n
147 Generate the path priority for Compaq/HP controller in
150 .B mpath_prio_hds_modular %b
151 Generate the path priority for Hitachi HDS Modular storage arrays.
153 Default value is \fBnone\fR.
157 Specify any device-mapper features to be used. The most common of
159 .I "1 queue_if_no_path"
160 Note that this can also be set via the
165 The default method used to determine the paths' state. Possible values
170 Read the first sector of the device
175 command to the device.
178 Query the EMC Clariion specific EVPD page 0xC0 to determine the path
182 Check the path state for HP storage arrays with Active/Standby firmware.
185 Check the path state for LSI/Engenio RDAC storage controller.
188 Read the first sector with direct I/O.
190 Default value is \fIreadsector0\fR.
194 Tell the daemon to manage path group failback, or not to. 0 or
196 means immediate failback, values >0 means deferred failback (in
199 means no failback. Default value is
203 The number of IO to route to a path before switching to the next in
204 the same path group. Default is
208 If set to \fIpriorities\fR the multipath configurator will assign
209 path weights as "path prio * rr_min_io". Possible values are
217 Specify the number of retries until disable queueing, or
219 for immediate failure (no queueing),
221 for never stop queueing. Default is 0.
223 .B user_friendly_names
226 , using the bindings file
227 .I /var/lib/multipath/bindings
228 to assign a persistent and unique alias to the multipath, in the form of mpath<n>.
231 use the WWID as the alias. In either case this be will
232 be overriden by any specific aliases in the \fImultipaths\fR section.
237 Specify the maximum number of file descriptors that can be opened by multipath
238 and multipathd. This is equivalent to ulimit -n. A value of \fImax\fR will set
239 this to the system limit from /proc/sys/fs/nr_open. If this is not set, the
240 maximum number of open fds is taken from the calling process. It is usually
241 1024. To be safe, this should be set to the maximum number of paths plus 32,
242 if that number is greated than 1024.
244 .SH "blacklist section"
247 section is used to exclude specific device from inclusion in the
248 multipath topology. It is most commonly used to exclude local disks or
249 LUNs for the array controller.
251 The following keywords are recognized:
254 The \fIWorld Wide Identification\fR of a device.
257 Regular expression of the device nodes to be excluded.
260 Subsection for the device description. This subsection recognizes the
264 keywords. For a full description of these keywords please see the
267 .SH "blacklist_exceptions section"
269 .I blacklist_exceptions
270 section is used to revert the actions of the
272 section, ie to include specific device in the
273 multipath topology. This allows to selectively include devices which
274 would normally be excluded via the
278 The following keywords are recognized:
281 The \fIWorld Wide Identification\fR of a device.
284 Regular expression of the device nodes to be excluded.
287 Subsection for the device description. This subsection recognizes the
291 keywords. For a full description of these keywords please see the
294 .SH "multipaths section"
295 The only recognized attribute for the
303 subsection recognizes the following attributes:
306 Index of the container. Mandatory for this subsection.
309 (Optional) symbolic name for the multipath map.
311 The following attributes are optional; if not set the default values
319 .B path_grouping_policy
331 .SH "devices section"
332 The only recognized attribute for the
340 subsection recognizes the following attributes:
343 (Mandatory) Vendor identifier
346 (Mandatory) Product identifier
349 Product strings to blacklist for this vendor
352 (Optional) The hardware handler to use for this device type.
353 The following hardware handler are implemented:
357 Hardware handler for EMC storage arrays.
360 The following attributes are optional; if not set the default values
368 .B path_grouping_policy
395 processes being hung and not killable in situations where all the paths to the LUN go offline.
396 It is advisable to use the
406 was developed by Christophe Varoqui, <christophe.varoqui@free.fr> and others.