multipath
 

hi,
how can i setup multipath in active active mode?Centos 6.
somehow mpathconf --enable?
what else?
in order multipath -ll to show the 2 paths active-active the SAN which is connected must to be active active capable?
thank you

To run active-active the SAN must support it. For some arrays you need to blacklist the controller in multipath.conf, but usually just enable and you should see your paths.

hi,
it mean if i mpathconf --enable and SAN is active active capable then i see in multipath -ll active-active mode.right?
i have
multipath -ll
mpatha (1IET 00010001) dm-2 IET,VIRTUAL-DISK
size=20G features='0' hwhandler='0' wp=rw
|-+- policy='round-robin 0' prio=1 status=active
| `- 3:0:0:1 sdb 8:16 active ready running
`-+- policy='round-robin 0' prio=1 status=enabled
`- 4:0:0:1 sdc 8:32 active ready running

this is active standby.right? i have status=active status=enabled
thank you

You should review this: https://access.redhat.com/documentat...ath/mpio_setup

What is in your multipath.conf?

hi,
more /etc/multipath.conf
# This is a basic configuration file with some examples, for device mapper
# multipath.
# For a complete list of the default configuration values, see
# /usr/share/doc/device-mapper-multipath-0.4.9/multipath.conf.defaults
# For a list of configuration options with descriptions, see
# /usr/share/doc/device-mapper-multipath-0.4.9/multipath.conf.annotated
#
# REMEMBER: After updating multipath.conf, you must run
#
# service multipathd reload
#
# for the changes to take effect in multipathd

## By default, devices with vendor = "IBM" and product = "S/390.*" are
## blacklisted. To enable mulitpathing on these devies, uncomment the
## following lines.
#blacklist_exceptions {
# device {
# vendor "IBM"
# product "S/390.*"
# }
#}

##
## Here is an example of how to configure some standard options.
##
#
#defaults {
# udev_dir /dev
# polling_interval 10
# path_selector "round-robin 0"
# path_grouping_policy multibus
# getuid_callout "/lib/udev/scsi_id --whitelisted --device=/dev/%
n"
# prio alua
# path_checker readsector0
# rr_min_io 100
# max_fds 8192
# rr_weight priorities
# failback immediate
# no_path_retry fail
# user_friendly_names yes
#}
##
## The wwid line in the following blacklist section is shown as an example
## of how to blacklist devices by wwid. The 2 devnode lines are the
## compiled in default blacklist. If you want to blacklist entire types
## of devices, such as all scsi devices, you should use a devnode line.
## However, if you want to blacklist specific devices, you should use
## a wwid line. Since there is no guarantee that a specific device will
## not change names on reboot (from /dev/sda to /dev/sdb for example)
## devnode lines are not recommended for blacklisting specific devices.
##
#blacklist {
# wwid 26353900f02796769
# devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
# devnode "^hd[a-z]"
#}
#multipaths {
# multipath {
# wwid 3600508b4000156d700012000000b0000
# 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
# }
#}
#devices {
# device {
# vendor "COMPAQ "
# product "HSV110 (C)COMPAQ"
# path_grouping_policy multibus
# getuid_callout "/lib/udev/scsi_id --whitelisted --devic
e=/dev/%n"
# path_checker readsector0
# path_selector "round-robin 0"
# hardware_handler "0"
# failback 15
# rr_weight priorities
# no_path_retry queue
# }
# device {
# vendor "COMPAQ "
# product "MSA1000 "
# path_grouping_policy multibus
# }
#}

blacklist {
}

Set the path_grouping_policy to multibus.

Right now, you are using the default path_grouping_policy, failover. If I remember this well, failover puts each path in its own priority group, and if one group fails, one of the others takes over. multibus will put your paths in the same group.

You can then use the path_selector option to configure a more sophisticated algorithm than round-robin.

See the multipath.conf man page.

hi,
i modified in multipath.conf
defaults {
path_grouping_policy multibus
}


multipath -ll
Jan 03 11:28:15 | /etc/multipath.conf line 32, duplicate keyword: defaults
mpatha (1IET 00010001) dm-2 IET,VIRTUAL-DISK
size=20G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 3:0:0:1 sdc 8:32 active ready running
`- 4:0:0:1 sdb 8:16 active ready running


the both path are active.tnx