James Fillman wrote:
> I'm running RHEL5 with QLogic HBA's and a Sun 6140 SAN. The host type
> I'm using for my servers is 'Solaris (with DMP)'. This turns AVT mode
> one. For some reason, the two controllers are returning the same
> priority value to my priority call out program (mpath_prio_tpc).
>
> 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@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]
>
> Where is should be:
>
> [root@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=3][active]
> \_ 1:0:0:2 sdd 8:48 [active][ready]
> \_ round-robin 0 [prio=0][active]
> \_ 1:0:1:2 sdg 8:96 [active][ready]
>
> I've gotten this working at my other data center with the same
> hardware/software configuration. At the moment, I'm pointing my finger
> at the SAN hardware but I don't have much to back it up with.
>
> here's my multipath.conf file:
>
> blacklist
> {
> devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st|sda)[0-9]*"
> }
>
> defaults
> {
> udev_dir /dev
> polling_interval 10
> selector "round-robin 0"
> path_grouping_policy group_by_prio
> getuid_callout "/sbin/scsi_id -g -u -s /block/%n"
> prio_callout "/sbin/mpath_prio_tpc /dev/%n"
> path_checker readsector0
> rr_min_io 100
> rr_weight priorities
> failback immediate
> no_path_retry queue
> user_friendly_name yes
> }
>
> devnode_blacklist
> {
> devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st|sda)[0-9]*"
> devnode "^hd[a-z][0-9]*"
> devnode "^cciss!c[0-9]d[0-9]*"
> }
>
> multipaths
> {
> multipath
> {
> wwid 3600a0b800029cc400000120946e56616
> alias mdi_deploys
> }
> multipath
> {
> wwid 3600a0b800029f8e80000064d46e565e7
> alias mdi_logging
> }
> multipath
> {
> wwid 3600a0b800029cc4000001140468531fa
> alias primary_logging
> }
> }
>
> devices
> {
> device
> {
> vendor "SUN"
> product "CSM200_R"
> path_grouping_policy group_by_prio
> path_checker readsector0
> prio_callout "/sbin/mpath_prio_tpc /dev/%n"
> getuid_callout "/sbin/scsi_id -g -u -s
> /block/%n"
> rr_weight uniform
> rr_min_io 1000
> features "1 queue_if_no_path"
> }
> }
>
Oh, please _don't_ use
rr_weight priorities
The implementation is broken (I send a patch once but it got rejected)
and it's completely useless when using 'group_by_prio'.
rr_weight = priorities is meant to adjust the round-robin scheduler by
the priority of each path. However, when using group_by_prio you'll the
same priority for all paths in a group. So effectively you only increase
(actually, you would increase if it would be working properly) the rr_min_io
value by the priority value.
So please try without this setting.
As for the AVT setting: sg_vpd can decode the RDAC mode pages; please send
the output of
sg_vpd -p vac <devname>
That should give us some hints what's going on here.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
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