Dm-0 is full disk and dm-1 is your partition. Just take it as is, this is the way device-mapper works :)
--- With best regards
Andrey Borzenkov Senior system engineer Service operations
-----Original Message----- From: toasters-bounces@teaparty.net [mailto:toasters-bounces@teaparty.net] On Behalf Of Paul Letta Sent: Monday, October 03, 2011 4:49 PM To: toasters@teaparty.net Subject: Linux Mutipath to NetApp LUN via FCP
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" } } _______________________________________________ Toasters mailing list Toasters@teaparty.net http://www.teaparty.net/mailman/listinfo/toasters