Wednesday, January 19, 2011

Multipath Tips


Multipath Tips

·         Check necessary multipath-tools package are installed
·         chkconfig multipathd on
  
Activate multipath service:

service multipathd start


Find out WWIDs: 

#multipath -v2 -d


Activate multipaths:

#multipath -v2


Will show multipath luns and groups. Look for the multipath group number, this is the dm-# listed in /proc/partitions. The multipath lun is accessed via the /dev/dm-# device entry


Verify the multipath:

#multipath –l

It will list the complete multipath list for example:
[root@baskar.com ~]# multipath -ll
LUN1 (360050768018e827fa000000000000154) dm-7 IBM,2145
[size=200G][features=1 queue_if_no_path][hwhandler=0][rw]
\_ round-robin 0 [prio=100][active]
 \_ 3:0:1:1 sde 8:64  [active][ready]
 \_ 4:0:1:1 sdi 8:128 [active][ready]
\_ round-robin 0 [prio=20][enabled]
 \_ 3:0:0:1 sdc 8:32  [active][ready]
 \_ 4:0:0:1 sdg 8:96  [active][ready]
LUN0 (360050768018e827fa000000000000153) dm-6 IBM,2145
[size=200G][features=1 queue_if_no_path][hwhandler=0][rw]
\_ round-robin 0 [prio=100][active]
 \_ 3:0:0:0 sdb 8:16  [active][ready]
 \_ 4:0:0:0 sdf 8:80  [active][ready]
\_ round-robin 0 [prio=20][enabled]
 \_ 3:0:1:0 sdd 8:48  [active][ready]
 \_ 4:0:1:0 sdh 8:112 [active][ready]

·         verify (you should see sensible device names in the output):
#ls -la /dev/mapper

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