[dm-devel] path priorities on Sun's 6140

[Eckebrecht von Pappenheim]

Hi,

> Can anyone briefly explain what the mpath_prio_tpc utility does and
> where these priority values come from?
> 
> The output of multipath -v2 -ll is:
> 
> [root at vlxq02md cluster]# multipath -v2 -ll
> mdi_logging (3600a0b800029f8e80000064d46e565e7) dm-9 SUN,CSM200_R
> [size=100G][features=1 queue_if_no_path][hwhandler=0]
> \_ round-robin 0 [prio=0][active]
>  \_ 1:0:0:2 sdd 8:48  [active][ready]
>  \_ 1:0:1:2 sdg 8:96  [active][ready]

you are sure your two pathes are using different controllers? A SAN setup
problem which makes the HBA use only 1 of the two controllers seems to be a
very good reason for this multipath output.

Do you use a single-port HBA? 

With my dual-port HBA I get:

Raid5_for_IMAP-Volume (3600a0b80002906e20000089345bf1a2b) dm-1 SUN,CSM200_R
[size=1.4T][features=0][hwhandler=0]
\_ round-robin 0 [prio=12][active]
 \_ 7:0:1:1  sdac 65:192 [active][ready] 
 \_ 6:0:3:1  sds  65:32  [active][ready] 
\_ round-robin 0 [prio=2][enabled]
 \_ 7:0:3:1  sdam 66:96  [active][ready] 
 \_ 6:0:1:1  sdi  8:128  [active][ready]


with multipath.conf:

devices {
        device {
                vendor SUN
                product CSM200_R
                path_grouping_policy group_by_prio
                path_checker tur
                prio_callout "mpath_prio_tpc /dev/%n"
                features "1 queue_if_no_path"
        }
}


BTW: A polling interval of 10 seconds is too slow for 6140 firmware
updates, 
I had to use 5 seconds because the controllers are rebooting quite fast...

regards,
Eckebrecht

-- 
Eckebrecht von Pappenheim
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