Multipath issue with SLES 11 SP2

SUSE Linux Enterprise Desktop SLED Configure-Administer
1

Hi,

I installed Boot from SAN (FC) SLES 11 SP2 using GUI.
The default multipath configuration seems not good because each path group contains just only one path and round-robin configuration doesn’t really apply between all paths. :confused:
This configuration is the default OS configuration and I didn’t change a thing after.

What I get by default

mpatha (xxxxxxxxxxxxxxxx) dm-0 XXX,XXXXXX
size=48G features=‘1 queue_if_no_path’ hwhandler=‘0’ wp=rw
|-± policy=‘round-robin 0’ prio=1 status=active
| - 0:0:4:1 sdc 8:32 active ready running |-+- policy='round-robin 0' prio=1 status=enabled | - 0:0:5:1 sdd 8:48 active ready running
|-± policy=‘round-robin 0’ prio=1 status=enabled
| - 1:0:3:1 sdh 8:112 active ready running |-+- policy='round-robin 0' prio=1 status=enabled | - 1:0:5:1 sdi 8:128 active ready running
|-± policy=‘round-robin 0’ prio=1 status=enabled
| - 0:0:7:1 sde 8:64 active ready running |-+- policy='round-robin 0' prio=1 status=enabled | - 0:0:3:1 sdb 8:16 active ready running
|-± policy=‘round-robin 0’ prio=1 status=enabled
| - 1:0:7:1 sdj 8:144 active ready running |-+- policy='round-robin 0' prio=1 status=enabled | - 1:0:2:1 sdg 8:96 active ready running
|-± policy=‘round-robin 0’ prio=1 status=enabled
| - 1:0:0:1 sdf 8:80 active ready running -± policy=‘round-robin 0’ prio=1 status=enabled
`- 0:0:1:1 sda 8:0 active ready running

What I think I should get

mpatha (xxxxxxxxxxxxxxxx) dm-0 XXX,XXXXXX
size=48G features=‘1 queue_if_no_path’ hwhandler=‘0’ wp=rw
-+- policy='round-robin 0' prio=1 status=active |- 0:0:4:1 sdc 8:32 active ready running |- 0:0:5:1 sdd 8:48 active ready running |- 1:0:3:1 sdh 8:112 active ready running |- 1:0:5:1 sdi 8:128 active ready running |- 0:0:7:1 sde 8:64 active ready running |- 0:0:3:1 sdb 8:16 active ready running |- 1:0:7:1 sdj 8:144 active ready running |- 1:0:2:1 sdg 8:96 active ready running |- 1:0:0:1 sdf 8:80 active ready running - 0:0:1:1 sda 8:0 active ready running

2

[QUOTE=elizada;13712]Hi,

I installed Boot from SAN (FC) SLES 11 SP2 using GUI.
The default multipath configuration seems not good…[/QUOTE]

Which SAN do you have attached specifically (Make & model number)?

Also, how many paths are there from server to SAN? I’m surprised to see that many paths for one device.

Cheers,
Willem

3

Hi,

I’m using XIV storage controller, model 2810
XIV works as grid and it’s recommended to zone your host with many as possible interfaces, so this why you can see so many paths

4

[QUOTE=elizada;13812]Hi,

I’m using XIV storage controller, model 2810
XIV works as grid and it’s recommended to zone your host with many as possible interfaces, so this why you can see so many paths[/QUOTE]

Hi Elizada,

Thanks for the info. I don’t have personal experience with this SAN, but it could have to do with how you have set the devices section for this SAN in /etc/multipath.conf.

From the settings I normally do for our SANS + this link : http://pic.dhe.ibm.com/infocenter/strhosts/ic/topic/com.ibm.help.strghosts.doc/HAK/1.8.0/HAG/hak_ug_ch8_multipath_config.html

Maybe these settings would get you the right results (use with care):

devices {
        device {
                vendor 			"IBM"
                product 		"2810XIV"
		path_selector 		"round-robin 0"
                #or try#path_selector	"queue-length 0"
                path_grouping_policy	multibus
                rr_min_io          	15
		rr_weight         	priorities
                features                "1 no_partitions"
                path_checker 		tur
                failback 		15
		no_path_retry 		queue
                no_path_retry 5
		features                "0"
polling_interval 3
}

Posting your current multipath.conf (in total) could shed some light on why you are seeing what you are seeing.

Cheers,
Willem