Red Hat CLUSTER SUITE 4.7 DM MULTIPATH, Руководство по настройке и администрированию

Страница: 27 / 38

Configuration File Devices
17
multipaths {
multipath {
wwid 3600508b4000156d70001200000b0000
alias yellow
path_grouping_policy multibus
path_checker readsector0
path_selector "round-robin 0"
failback manual
rr_weight priorities
no_path_retry 5
}
multipath {
wwid 1DEC_____321816758474
alias red
rr_weight priorities
}
}
4.5. Configuration File Devices
Table 4.3, “Device Attributes”
shows the attributes that you can set for each individual storage device
in the
devices
section of the
multipath.conf
configuration file. These attributes are used by DM-
Multipath unless they are overwritten by the attributes specified in the
multipaths
section of the
multipath.conf
file for paths that contain the device. These attributes override the attributes set in
the
defaults
section of the
multipath.conf
file.
Many devices that support multipathing are included by default in a multipath configuration. The values
for the devices that are supported by default are listed in the
multipath.conf.defaults
file.
You probably will not need to modify the values for these devices, but if you do you can overwrite the
default values by including an entry in the the configuration file for the device that overwrites those
values. You can copy the device configuration defaults from the
multipath.conf.defaults
file for
the device and override the values that you want to change.
To add a device to this section of the configuration file that is not configured automatically by default,
you need to set the
vendor
and
product
parameters. You can find these values by looking at
/sys/
block/ device_name /device/vendor
and
/sys/block/ device_name /device/model
where
device_name
is the device to be multipathed, as in the following example:
[root@cypher-06 ~]# cat /sys/block/sda/device/vendor
WINSYS
[root@cypher-06 ~]#
cat /sys/block/sda/device/model
SF2372
The additional parameters to specify depend on your specific device. If the device is active/active, you
will usually not need to set additional parameters. You may want to set
path_grouping_policy
to
multibus
. Other parameters you may need to set are
no_path_retry
and
rr_min_io
, as
described in
Table 4.3, “Device Attributes”
.