Multipath and iSCSI on 11.10

[Albert Chin]

On Fri, Dec 23, 2011 at 07:20:01PM -0600, Albert Chin wrote:
> I have device-mapper-multipath configured with iSCSI. I have two
> interfaces configured to communicate with the iSCSI server. I discover
> and connect with the iSCSI targets as follows:
>   (1) # iscsiadm -m discovery -t st -p 10.191.61.1:3260 -I iface1 -P 1
>   (2) # iscsiadm -m discovery -t st -p 10.191.62.1:3260 -I iface2 -P 1
>   (3) # iscsiadm -m node -p 10.191.61.1:3260 -I iface1 -l
>   (4) # iscsiadm -m node -p 10.191.62.1:3260 -I iface2 -l
>   # cat /etc/multipath.conf
>   defaults {
>     selector             "round-robin 0"
>     udev_dir             /dev
>     user_friendly_names  yes
>   }
>   [[ snip snip ]]
>   # multipath -ll
>   winry (3600144f057774b0000004eeab58a0001) dm-24 OI,COMSTAR
>   size=500G features='0' hwhandler='0' wp=rw
>   |-+- policy='round-robin 0' prio=1 status=active
>   | `- 12:0:0:0 sdd  8:48   active ready running
>   `-+- policy='round-robin 0' prio=1 status=enabled
>     `- 41:0:0:0 sdae 65:224 active ready running
>   sai (3600144f057774b0000004ebf539e001d) dm-9 OI,COMSTAR
>   size=500G features='0' hwhandler='0' wp=rw
>   |-+- policy='round-robin 0' prio=1 status=active
>   | `- 17:0:0:0 sdv  65:80  active ready running
>   `-+- policy='round-robin 0' prio=1 status=enabled
>     `- 54:0:0:0 sdai 66:32  active ready running
>   ...
> 
> 1. Based on the above multipath -ll output, it seems that I am not
>    load-balancing across both NICs. Why not? 

Adding path_grouping_policy multibus fixed this.

> 2. When I boot the system, the initiator does not log in to any
>    target. Therefore, I need to rerun (3) and (4) above. Why?

Still not sure about this one.

-- 
albert chin (china at thewrittenword.com)