1MULTIPATH.CONF(5) File Formats Manual MULTIPATH.CONF(5)
2
6 multipath.conf - multipath daemon configuration file
7
9 multipath.conf is the configuration file for the multipath daemon. It
10 is used to overwrite the built-in configuration table of multipathd.
11 Any line whose first non-white-space character is a '#' is considered a
12 comment line. Empty lines are ignored.
13
15 The configuration file contains entries of the form:
16 <section> {
18 <attribute> <value>
19 ...
20 <subsection> {
21 <attribute> <value>
22 ...
23 }
24 }
25 Each section contains one or more attributes or subsections. The recog‐
27 nized keywords for attributes or subsections depend on the section in
28 which they occor.
29 The following section keywords are recognized:
31 defaults This section defines default values for attributes
33 which are used whenever no specific setting is given.
34 blacklist This section defines which devices should be excluded
36 from the multipath topology discovery.
37 blacklist_exceptions
39 This section defines which devices should be included
40 in the multipath topology discovery, despite being
41 listed in the blacklist section.
42 multipaths This section defines the multipath topologies. They
44 are indexed by a World Wide Identifier(wwid), which is
45 the result of the getuid_callout program.
46 devices This section defines the device-specific settings.
48
50 The defaults section recognizes the following keywords:
51 polling_interval interval between two path checks in seconds For prop‐
53 erly functioning paths, the interval between checks
54 will gradually increase to (4 * polling_interval);
55 default is 5
56 udev_dir directory where udev creates its device nodes; default
58 is /dev
59 verbosity default verbosity. Higher values increase the ver‐
61 bosity level. Valid levels are between 0 and 6;
62 default is 2
63 selector The default path selector algorithm to use; they are
65 offered by the kernel multipath target. The only cur‐
66 rently implemented is round-robin 0
67 path_grouping_policy
69 The default path grouping policy to apply to unspeci‐
70 fied multipaths. Possible values are
71 failover 1 path per priority group
73 multibus all paths in 1 priority group
75 group_by_serial
77 1 priority group per serial number
78 group_by_prio
80 1 priority group per priority value. Pri‐
81 orities are determined by callout programs
82 specified as a global, per-controller or
83 per-multipath option in the configuration
84 file.
85 group_by_node_name
87 1 priority group per target node name.
88 Target node names are fetched in
89 /sys/class/fc_transport/target*/node_name.
90 Default value is multibus.
92 getuid_callout The default program and args to callout to obtain a
94 unique path identifier. Should be specified with an
95 absolute path. Default value is /lib/udev/scsi_id
96 --whitelisted --device=/dev/%n
97 prio_callout The default program and args to callout to obtain a
99 path priority value. The specified program will be
100 executed and should return a numeric value specifying
101 the relative priority of this path. Higher number have
102 a higher priority. A '%n' in the command line will be
103 expanded to the device name, a '%b' will be expanded
104 to the device number in major:minor format. none is a
105 valid value. Currently the following path priority
106 programs are implemented:
107 mpath_prio_emc /dev/%n
109 Generate the path priority for EMC arrays
110 mpath_prio_alua /dev/%n
112 Generate the path priority based on the
113 SCSI-3 ALUA settings.
114 mpath_prio_netapp /dev/%n
116 Generate the path priority for NetApp
117 arrays.
118 mpath_prio_rdac /dev/%n
120 Generate the path priority for LSI/Engenio
121 RDAC controller.
122 mpath_prio_hp_sw /dev/%n
124 Generate the path priority for Compaq/HP
125 controller in active/standby mode.
126 mpath_prio_hds_modular %b
128 Generate the path priority for Hitachi HDS
129 Modular storage arrays.
130 Default value is none.
132 features Specify any device-mapper features to be used. The
134 most common of these features is 1 queue_if_no_path
135 Note that this can also be set via the no_path_retry
136 keyword.
137 path_checker The default method used to determine the paths' state.
139 Possible values are
140 readsector0 Read the first sector of the device
142 tur Issue a TEST UNIT READY command to the
144 device.
145 emc_clariion
147 Query the EMC Clariion specific EVPD page
148 0xC0 to determine the path state.
149 hp_sw Check the path state for HP storage arrays
151 with Active/Standby firmware.
152 rdac Check the path state for LSI/Engenio RDAC
154 storage controller.
155 directio Read the first sector with direct I/O.
157 Default value is readsector0.
159 failback Tell the daemon to manage path group failback, or not
161 to. 0 or immediate means immediate failback, values >0
162 means deferred failback (in seconds). manual means no
163 failback. Default value is manual
164 rr_min_io The number of IO to route to a path before switching
166 to the next in the same path group. Default is 1000
167 rr_weight If set to priorities the multipath configurator will
169 assign path weights as "path prio * rr_min_io". Possi‐
170 ble values are priorities or uniform uniform
171 no_path_retry Specify the number of retries until disable queueing,
173 or fail for immediate failure (no queueing), queue for
174 never stop queueing. Default is 0.
175 user_friendly_names
177 If set to yes , using the bindings file /etc/multi‐
178 path/bindings to assign a persistent and unique alias
179 to the multipath, in the form of mpath<n>. If set to
180 no use the WWID as the alias. In either case this be
181 will be overriden by any specific aliases in the mul‐
182 tipaths section. Default is no
183 max_fds Specify the maximum number of file descriptors that
185 can be opened by multipath and multipathd. This is
186 equivalent to ulimit -n. A value of max will set this
187 to the system limit from /proc/sys/fs/nr_open. If this
188 is not set, the maximum number of open fds is taken
189 from the calling process. It is usually 1024. To be
190 safe, this should be set to the maximum number of
191 paths plus 32, if that number is greated than 1024.
192 fast_io_fail_tmo Specify the number of seconds the scsi layer will wait
194 after a problem has been detected on a FC remote port
195 before failing IO to devices on that remote port.
196 This should be smaller than dev_loss_tmo. Setting this
197 to off will disable the timeout.
198 dev_loss_tmo Specify the number of seconds the scsi layer will wait
200 after a problem has been detected on a FC remote port
201 before removing it from the system.
202
204 The blacklist section is used to exclude specific device from inclusion
205 in the multipath topology. It is most commonly used to exclude local
206 disks or LUNs for the array controller.
207 The following keywords are recognized:
209 wwid The World Wide Identification of a device.
211 devnode Regular expression of the device nodes to be excluded.
213 device Subsection for the device description. This subsection
215 recognizes the vendor and product keywords. For a full
216 description of these keywords please see the devices
217 section description.
218
220 The blacklist_exceptions section is used to revert the actions of the
221 blacklist section, ie to include specific device in the multipath
222 topology. This allows to selectively include devices which would nor‐
223 mally be excluded via the blacklist section.
224 The following keywords are recognized:
226 wwid The World Wide Identification of a device.
228 devnode Regular expression of the device nodes to be excluded.
230 device Subsection for the device description. This subsection
232 recognizes the vendor and product keywords. For a full
233 description of these keywords please see the devices
234 section description.
235
237 The only recognized attribute for the multipaths section is the multi‐
238 path subsection.
239 The multipath subsection recognizes the following attributes:
241 wwid Index of the container. Mandatory for this subsection.
243 alias (Optional) symbolic name for the multipath map.
245 The following attributes are optional; if not set the default values
247 are taken from the defaults section:
248 path_grouping_policy
250 path_selector
251 failback
252 no_path_retry
253 rr_min_io
254
256 The only recognized attribute for the devices section is the device
257 subsection.
258 The device subsection recognizes the following attributes:
260 vendor (Mandatory) Vendor identifier
262 product (Mandatory) Product identifier
264 product_blacklist
266 Product strings to blacklist for this vendor
267 hardware_handler (Optional) The hardware handler to use for this device
269 type. The following hardware handler are implemented:
270 1 emc Hardware handler for EMC storage arrays.
272 The following attributes are optional; if not set the default values
274 are taken from the defaults section:
275 path_grouping_policy
277 getuid_callout
278 path_selector
279 path_checker
280 features
281 prio_callout
282 failback
283 rr_weight
284 no_path_retry
285 rr_min_io
286 fast_io_fail_tmo
287 dev_loss_tmo
288
290 The usage of queue_if_no_path option can lead to D state processes
291 being hung and not killable in situations where all the paths to the
292 LUN go offline. It is advisable to use the no_path_retry option
293 instead.
294
296 udev(8), dmsetup(8) multipath(8) multipathd(8)
297
299 multipath was developed by Christophe Varoqui, <christophe.varo‐
300 qui@free.fr> and others.
301 30 November 2006 MULTIPATH.CONF(5)