If you want to mount a multipath device during system boot, you need to install the multipath-tools-boot package.
The base Debian config for multipath looks something like this:
devices {
device {
vendor IBM
product "1726-2xx"
path_checker rdac
path_grouping_policy group_by_prio
prio_callout "/sbin/mpath_prio_rdac /dev/%n"
}
}
blacklist {
wwid 350025386000434ef
}
multipaths {
multipath {
wwid 3600a0b80003ad39d0000077351f058c0
alias friendly_name
}
}
The devices section needs to be updated for compatibility with the appropriate SAN.
The blacklist section can have multiple wwid lines. The WWID for any device that you do not want multipath to use can be determined by running /lib/udev/scsi_id --page=0x83 --whitelisted --device=/dev/sdX
The multipaths section will map a WWID to a friendly name. The WWID can be determined using the same command as above.
If successful, you will get a block device in /dev/mapper/friendly_name
You should be able to run multipath -ll to see the status:
root@machine:~# multipath -ll
Dec 19 13:21:43 | multipath.conf +7, invalid keyword: prio_callout
friendly_name (3600a0b80003ad39d0000077351f058c0) dm-5 IBM,1726-2xx FAStT
size=18T features='1 queue_if_no_path' hwhandler='1 rdac' wp=rw
`-+- policy='round-robin 0' prio=3 status=active
|- 7:0:0:0 sdc 8:32 active ready running
`- 8:0:0:0 sdd 8:48 active ready running