On Mon, 2013-10-21 at 11:05 -0500, Benjamin Marzinski wrote: > On Thu, Oct 17, 2013 at 12:03:10PM -0700, Frank Mayhar wrote: > > Dragging this back up into the light... > > > > On Thu, 2013-09-26 at 19:49 -0400, Mike Snitzer wrote: > > > Frank, I had a look at your patch. It leaves a lot to be desired, I was > > > starting to clean it up but ultimately found myself agreeing with > > > Alasdair's original point: that this policy should be implemented in the > > > userspace daemon. > > > > I've found and fixed a couple of bugs but I would still like to know > > what issues you had with the patch. As I said before, I would be more > > than happy to clean it up. > > > > In the time since we had this discussion, by the way, we ran into a > > problem that a userspace daemon can't solve: That of shutdown. We ran > > into a number of failures in which systems were hung for hours. It > > turned out that they were caused by a regular system shutdown. Our > > backing store is network-based and networking was getting killed before > > applications (as is usually the case), leaving I/O outstanding on the > > device. Since queue_if_no_path was set, the I/O wasn't dumped and our > > daemon was killed by shutdown very shortly thereafter so it couldn't > > recover (otherwise it would have cleaned things up). > > > > Was multipathd force killed? What was the default configuration > parameter "queue_without_daemon" set to? > > If "queue_without_daemon" is set to "no", multipathd should disable > queueing when it is stopped. This was added specifically to avoid this > issue. We don't run multipathd (we need our own daemon for various reasons) and we're also running an older kernel (based on 3.3), so we don't have "queue_without_daemon" yet. (In fact, I don't see it on a cursory glance at dm-mpath.c; where is it implemented?) -- Frank Mayhar 310-460-4042 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
