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; default is
74 directory where udev creates its device nodes; default is
78 default verbosity. Higher values increase the verbosity level. Valid
79 levels are between 0 and 6; default is 2.
83 The default path selector algorithm to use; they are offered by the
84 kernel multipath target. The only currently implemented is
87 .B path_grouping_policy
88 The default path grouping policy to apply to unspecified
89 multipaths. Possible values are
93 1 path per priority group
96 all paths in 1 priority group
99 1 priority group per serial number
102 1 priority group per priority value. Priorities are determined by
103 callout programs specified as a global, per-controller or
104 per-multipath option in the configuration file.
106 .B group_by_node_name
107 1 priority group per target node name. Target node names are fetched
108 in /sys/class/fc_transport/target*/node_name.
110 Default value is \fImultibus\fR.
114 The default program and args to callout to obtain a unique path
115 identifier. Should be specified with an absolute path. Default value
117 .I /lib/udev/scsi_id --whitelisted --device=/dev/%n
120 The default program and args to callout to obtain a path priority
121 value. The specified program will be executed and should return a
122 numeric value specifying the relative priority of this path. Higher
123 number have a higher priority. A '%n' in the command line will be expanded
124 to the device name, a '%b' will be expanded to the device number in
128 is a valid value. Currently the following path priority programs are
132 .B mpath_prio_emc /dev/%n
133 Generate the path priority for EMC arrays
135 .B mpath_prio_alua /dev/%n
136 Generate the path priority based on the SCSI-3 ALUA settings.
138 .B mpath_prio_netapp /dev/%n
139 Generate the path priority for NetApp arrays.
141 .B mpath_prio_rdac /dev/%n
142 Generate the path priority for LSI/Engenio RDAC controller.
144 .B mpath_prio_hp_sw /dev/%n
145 Generate the path priority for Compaq/HP controller in
148 .B mpath_prio_hds_modular %b
149 Generate the path priority for Hitachi HDS Modular storage arrays.
151 Default value is \fBnone\fR.
155 Specify any device-mapper features to be used. The most common of
157 .I "1 queue_if_no_path"
158 Note that this can also be set via the
163 The default method used to determine the paths' state. Possible values
168 Read the first sector of the device
173 command to the device.
176 Query the EMC Clariion specific EVPD page 0xC0 to determine the path
180 Check the path state for HP storage arrays with Active/Standby firmware.
183 Check the path state for LSI/Engenio RDAC storage controller.
186 Read the first sector with direct I/O.
188 Default value is \fIreadsector0\fR.
192 Tell the daemon to manage path group failback, or not to. 0 or
194 means immediate failback, values >0 means deferred failback (in
197 means no failback. Default value is
201 The number of IO to route to a path before switching to the next in
202 the same path group. Default is
206 If set to \fIpriorities\fR the multipath configurator will assign
207 path weights as "path prio * rr_min_io". Possible values are
215 Specify the number of retries until disable queueing, or
217 for immediate failure (no queueing),
219 for never stop queueing. Default is 0.
221 .B user_friendly_names
224 , using the bindings file
225 .I /var/lib/multipath/bindings
226 to assign a persistent and unique alias to the multipath, in the form of mpath<n>.
229 use the WWID as the alias. In either case this be will
230 be overriden by any specific aliases in the \fImultipaths\fR section.
235 Specify the maximum number of file descriptors that can be opened by multipath
236 and multipathd. This is equivalent to ulimit -n. A value of \fImax\fR will set
237 this to the system limit from /proc/sys/fs/nr_open. If this is not set, the
238 maximum number of open fds is taken from the calling process. It is usually
239 1024. To be safe, this should be set to the maximum number of paths plus 32,
240 if that number is greated than 1024.
242 .SH "blacklist section"
245 section is used to exclude specific device from inclusion in the
246 multipath topology. It is most commonly used to exclude local disks or
247 LUNs for the array controller.
249 The following keywords are recognized:
252 The \fIWorld Wide Identification\fR of a device.
255 Regular expression of the device nodes to be excluded.
258 Subsection for the device description. This subsection recognizes the
262 keywords. For a full description of these keywords please see the
265 .SH "blacklist_exceptions section"
267 .I blacklist_exceptions
268 section is used to revert the actions of the
270 section, ie to include specific device in the
271 multipath topology. This allows to selectively include devices which
272 would normally be excluded via the
276 The following keywords are recognized:
279 The \fIWorld Wide Identification\fR of a device.
282 Regular expression of the device nodes to be excluded.
285 Subsection for the device description. This subsection recognizes the
289 keywords. For a full description of these keywords please see the
292 .SH "multipaths section"
293 The only recognized attribute for the
301 subsection recognizes the following attributes:
304 Index of the container. Mandatory for this subsection.
307 (Optional) symbolic name for the multipath map.
309 The following attributes are optional; if not set the default values
317 .B path_grouping_policy
329 .SH "devices section"
330 The only recognized attribute for the
338 subsection recognizes the following attributes:
341 (Mandatory) Vendor identifier
344 (Mandatory) Product identifier
347 Product strings to blacklist for this vendor
350 (Optional) The hardware handler to use for this device type.
351 The following hardware handler are implemented:
355 Hardware handler for EMC storage arrays.
358 The following attributes are optional; if not set the default values
366 .B path_grouping_policy
393 processes being hung and not killable in situations where all the paths to the LUN go offline.
394 It is advisable to use the
404 was developed by Christophe Varoqui, <christophe.varoqui@free.fr> and others.