[dm-devel] path checker in regards to failback

[Christophe Varoqui]

On jeu, 2006-02-09 at 12:39 -0700, Dale.R.Fowle at seagate.com wrote:
> Hi all, I have a question related to failover/failback. I'm running
> 0.4.5-0.11. I'm wondering what the path checker does for the multipathd
> daemon.
> 
> Here's my senario:
> I have two paths to a LUN, configure it with 'multipath -v 2 -p failover'.
> Run some I/O down the path of the /dev/mapper/<device>.
> I fail one of the paths either by pulling the fibre or disabling the port
> it's connected to.
> When I run 'multipath -ll' I see the failed path 'failed faulty'.
> I restore the path physically.
> Run 'multipath -ll' again to see the status and it's 'failed ready'.
> 
> Now, my question is, is multipathd supposed to handle making that path
> 'active ready'?

Yes, multipathd should reinstate the path upon checker status change
from "faulty" to "ready"

> I have 'failback immediate' set in the /etc/multipath.conf file. And it
> does do the immediate failback,...but based on the 'active ready' status.
> To get to that status, I have to actually issue a 'multipath' command to
> reinstate the path to active.
> 
Likely a bug you'll have to chase down a little.
Starting to challenge the devel branch would be a good idea, too.

> Is there something that I'm missing or am I just going to have to make a
> cron job run every few minutes to do path status updates?
> 
You should not need to resort to that.

Regards,
cvaroqui