Hi Everyone. This question is probably more Linux than Netapp, but I
figured people on this list have done this.
I am setting up DM-Multipath with a lun from a FAS via FCP. I have the
NetApp linux host utilities installed on the host.
I have a LUN that has 2 paths (one lun, 2 HA FAS controllers). Without
Multipath running, I see them as /dev/sdb and /dev/sdc:
# fdisk -l
Disk /dev/sdb: 322.1 GB, 322163441664 bytes
255 heads, 63 sectors/track, 39167 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 1 39167 314608896 83 Linux
Disk /dev/sdc: 322.1 GB, 322163441664 bytes
255 heads, 63 sectors/track, 39167 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdc1 1 39167 314608896 83 Linux
This is correct. I can mount each of these one at a time from the host
and see the LUN correctly.
After I start up Multipath, I have the same 2 devices above (sdb and
sdc) but TWO new devices:
Disk /dev/dm-0: 322.1 GB, 322163441664 bytes
255 heads, 63 sectors/track, 39167 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/dm-0p1 1 39167 314608896 83 Linux
Disk /dev/dm-1: 322.1 GB, 322159509504 bytes
255 heads, 63 sectors/track, 39166 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/dm-1 doesn't contain a valid partition table
My question is why do I have both /dev/dm-0 AND /dev/dm-1 ?
Also -- above shows dm-1 as not having a valid partition table,
However, when I try to mount /dev/dm-0 it fails (says its busy),
but I can mount /dev/dm-1 and see the LUN just fine.
So I'm looking for some basic guidance with multipath. From what I've read,
I should just see one /dev/dm-* and I should be able to mount it, and it
should
have a valid partition table on it.
Thanks !
Paul
Here is the /etc/multipath.conf file:
[root@zstore2 /]# cat /etc/multipath.conf
defaults {
user_friendly_names no
queue_without_daemon no
flush_on_last_del yes
max_fds max
pg_prio_calc avg
}
blacklist {
devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
devnode "^hd[a-z]"
devnode "^cciss.*"
wwid 3600508e00000000081661358cff52b01
}
devices {
device {
vendor "NETAPP"
product "LUN"
path_grouping_policy group_by_prio
features "1 queue_if_no_path"
prio_callout "/sbin/mpath_prio_ontap /dev/%n"
path_checker directio
failback immediate
hardware_handler "0"
rr_weight uniform
rr_min_io 128
getuid_callout "/sbin/scsi_id -g -u -s /block/%n"
}
}
