We started to notice that on our iSCSI hosts that are using Multipath that they seem to be sending most of the traffic across one port even though they have 4 paths for each mpath device. We are using a Hitachi SAN.
Here is my multipath configuration:
defaults {user_friendly_names yes
}
devices {
device {
vendor "HITACHI"
product "DF.*"
path_grouping_policy multibus
path_checker tur
getuid_callout "/sbin/scsi_id -g -u -s /block/%n"
no_path_retry 1
features "1 queue_if_no_path"
}
}
The output of multipath looks like:
mpath2 (360060e80101af190058baee900000007) dm-6 HITACHI,DF600F
size=1.5T features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=0 status=active
|- 8:0:0:1 sdg 8:96 active ready running
|- 9:0:0:1 sdh 8:112 active ready running
|- 7:0:0:1 sdf 8:80 active ready running
`- 10:0:0:1 sdi 8:128 active ready running
mpath0 (360060e80101af190058baee900000005) dm-5 HITACHI,DF600F
size=1.0T features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=0 status=active
|- 9:0:0:0 sdd 8:48 active ready running
|- 8:0:0:0 sdc 8:32 active ready running
|- 10:0:0:0 sde 8:64 active ready running
`- 7:0:0:0 sdb 8:16 active ready running
However when I do a tcpdump and count the number of packets to each of the IQN's they are not equal, not even close.
IQN1: 19,579
IQN2: 12,778
IQN3: 70,674
IQN4: 67
Is there anything I need to do in order to ensure that Multipath balances more evenly across all the paths???
Any help would be appreciated.
Devin
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