MULTIPATH.CONF(5)MULTIPATH.CONF(5)NAMEmultipath.conf - multipath daemon configuration file
DESCRIPTIONmultipath.conf is the configuration file for the multipath daemon. It
is used to overwrite the built-in configuration table of multipathd.
Any line whose first non-white-space character is a '#' is considered a
comment line. Empty lines are ignored.
SYNTAX
The configuration file contains entries of the form:
<section> {
<attribute> <value>
...
<subsection> {
<attribute> <value>
...
}
}
Each section contains one or more attributes or subsections. The recog‐
nized keywords for attributes or subsections depend on the section in
which they occor.
The following section keywords are recognized:
defaults This section defines default values for attributes
which are used whenever no values are given in the
appropriate device or multipath sections.
blacklist This section defines which devices should be excluded
from the multipath topology discovery.
blacklist_exceptions
This section defines which devices should be included
in the multipath topology discovery, despite being
listed in the blacklist section.
multipaths This section defines the multipath topologies. They
are indexed by a World Wide Identifier(wwid), which is
the result of the getuid_callout program.
devices This section defines the device-specific settings.
defaults section
The defaults section recognizes the following keywords:
polling_interval interval between two path checks in seconds; default
is 5
udev_dir directory where udev creates its device nodes; default
is /dev
selector The default path selector algorithm to use; they are
offered by the kernel multipath target. The only cur‐
rently implemented is round-robin 0
path_grouping_policy
The default path grouping policy to apply to unspeci‐
fied multipaths. Possible values are
failover 1 path per priority group
multibus all paths in 1 priority group
group_by_serial
1 priority group per serial number
group_by_prio
1 priority group per priority value. Pri‐
orities are determined by callout programs
specified as a global, per-controller or
per-multipath option in the configuration
file.
group_by_node_name
1 priority group per target node name.
Target node names are fetched in
/sys/class/fc_transport/target*/node_name.
Default value is multibus.
getuid_callout The default program and args to callout to obtain a
unique path identifier. Should be specified with an
absolute path. Default value is /sbin/scsi_id -g -u -s
prio_callout The default program and args to callout to obtain a
path priority value. The specified program will be
executed and should return a numeric value specifying
the relative priority of this path. Higher number have
a higher priority. A '%n' in the command line will be
expanded to the device name, a '%b' will be expanded
to the device number in major:minor format. none is a
valid value. Currently the following path priority
programs are implemented:
mpath_prio_emc /dev/%n
Generate the path priority for EMC arrays
mpath_prio_alua /dev/%n
Generate the path priority based on the
SCSI-3 ALUA settings.
mpath_prio_netapp /dev/%n
Generate the path priority for NetApp
arrays.
mpath_prio_tpc /dev/%n
Generate the path priority for LSI/Engenio
RDAC controller.
mpath_prio_hp_sw /dev/%n
Generate the path priority for Compaq/HP
controller in active/standby mode.
mpath_prio_hds_modular %b
Generate the path priority for Hitachi HDS
Modular storage arrays.
mpath_prio_weighted %n|%h <regex1> <prio1> [<regex2>
<prio2>] ...
Generate a path priority based on the
matching either the device name %n or the
H:B:T:L %h of the devices against a series
of regular expressions. WARNING: Both the
device name and the H:B:T:L of a device
can change when the node is rebooted, or
the device driver is reloaded. If you use
this callout it may be necessary to manu‐
ally edit your regular expressions when‐
ever either of these events occurs. NOTE:
The regular expression must match the com‐
plete device name or H:B:T:L. For instance
a regular expression of sda will only
match a device named sda, not sdaa, sdab,
etc. To match all of them, you would need
to use the regular expression sda.*
Default value is none.
features Specify any device-mapper features to be used. The
most common of these features is 1 queue_if_no_path
Note that this can also be set via the no_path_retry
keyword.
path_checker The default method used to determine the paths' state.
Possible values are
readsector0 Read the first sector of the device
tur Issue a TEST UNIT READY command to the
device.
emc_clariion
Query the EMC Clariion specific EVPD page
0xC0 to determine the path state.
hp_sw Check the path state for HP storage arrays
with Active/Standby firmware.
rdac Check the path state for LSI/Engenio RDAC
storage controller.
directio Read the first sector with direct I/O.
Default value is readsector0.
failback Tell the daemon to manage path group failback, or not
to. 0 or immediate means immediate failback, values >0
means deferred failback (in seconds). manual means no
failback. Default value is manual
rr_min_io The number of IO to route to a path before switching
to the next in the same path group. Default is 1000
rr_weight If set to priorities the multipath configurator will
assign path weights as "path prio * rr_min_io". Possi‐
ble values are priorities or uniform uniform
no_path_retry Specify the number of retries until disable queueing,
or fail for immediate failure (no queueing), queue for
never stop queueing. Default is 0.
max_fds Sets the maximum number of open file descriptors for
the multipathd process. Setting this to max will
cause multipathd to use the maximum number of open
file descriptors allowed by the system.
verbosity Sets the verbosity level for the multipath and multi‐
pathd commands. It is overridden by the -v command
line option. Valid values are from 0 to 6. Default is
2.
flush_on_last_del
Setting this to yes will cause multipathd to disable
queueing on a multipath device when the last path to
the device has been deleted. Default is no
queue_without_daemon
Setting this to no will cause multipathd to disable
queueing for all multipath devices when it is shut‐
down. Default is yes
bindings_file Sets the location for the multipath bindings file that
is used with the user_friendly_names option. Default
is /etc/multipath_bindings
mode The mode to use for the multipath device nodes, in
octal.
uid The numeric uid to use for the multipath device nodes.
gid The numeric gid to use for the multipath device nodes.
user_friendly_names
If set to yes , using the bindings file /var/lib/mul‐
tipath/bindings to assign a persistent and unique
alias to the multipath, in the form of mpath<n>. If
set to no use the WWID as the alias. In either case
this be will be overriden by any specific aliases in
the multipaths section. Default is no
blacklist section
The blacklist section is used to exclude specific device from inclusion
in the multipath topology. It is most commonly used to exclude local
disks or LUNs for the array controller.
The following keywords are recognized:
wwid The World Wide Identification of a device.
devnode Regular expression of the device nodes to be excluded.
device Subsection for the device description. This subsection
recognizes the vendor and product keywords. For a full
description of these keywords please see the devices
section description.
blacklist_exceptions section
The blacklist_exceptions section is used to revert the actions of the
blacklist section, ie to include specific device in the multipath
topology. This allows to selectively include devices which would nor‐
mally be excluded via the blacklist section.
The following keywords are recognized:
wwid The World Wide Identification of a device.
devnode Regular expression of the device nodes to be excluded.
device Subsection for the device description. This subsection
recognizes the vendor and product keywords. For a full
description of these keywords please see the devices
section description.
multipaths section
The only recognized attribute for the multipaths section is the multi‐
path subsection.
The multipath subsection recognizes the following attributes:
wwid Index of the container. Mandatory for this subsection.
alias (Optional) symbolic name for the multipath map.
The following attributes are optional; if not set the default values
are taken from the defaults section:
path_grouping_policy
prio_callout
path_selector
failback
no_path_retry
rr_min_io
rr_weight
flush_on_last_del
mode
uid
gid
devices section
The only recognized attribute for the devices section is the device
subsection.
The device subsection recognizes the following attributes:
vendor (Mandatory) Vendor identifier
product (Mandatory) Product identifier
product_blacklist
Product strings to blacklist for this vendor
hardware_handler (Optional) The hardware handler to use for this device
type. The following hardware handler are implemented:
1 emc Hardware handler for EMC storage arrays.
The following attributes are optional; if not set the default values
are taken from the defaults section:
path_grouping_policy
getuid_callout
path_selector
path_checker
features
prio_callout
failback
rr_weight
no_path_retry
rr_min_io
flush_on_last_del
SEE ALSOudev(8), dmsetup(8)multipath(8)multipathd(8)AUTHORS
multipath was developed by Christophe Varoqui, <christophe.varo‐
qui@free.fr> and others.
30 November 2006 MULTIPATH.CONF(5)
