Unfortunately, we still have a hang: https://gist.github.com/4347052/download On Wed, Dec 19, 2012 at 2:42 PM, Alex Elder <elder@xxxxxxxxxxx> wrote: > On 12/19/2012 03:25 PM, Alex Elder wrote: >> On 12/18/2012 12:05 PM, Nick Bartos wrote: >>> I've added the output of "ps -ef" in addition to triggering a trace >>> when a hang is detected. Not much is generally running at that point, >>> but you can have a look: >>> >>> https://gist.github.com/raw/4330223/2f131ee312ee43cb3d8c307a9bf2f454a7edfe57/rbd-hang-1355851498.txt >> >> This helped a lot. I updated the bug with a little more info. >> >> http://tracker.newdream.net/issues/3519 >> >> I also think I have now found something that could explain what you >> are seeing, and am developing a fix. I'll provide you an update >> as soon as I have tested what I come up with, almost certainly >> this afternoon. > > Nick, I have a new branch for you to try with a new fix in place. > As you might have predicted, it's named "wip-nick-newest". > > Please give it a try to see if it resolved the hang you've > been seeing and let me know how it goes. If it continues > to hang, please provide the logs as you have before, it's > been very helpful. > > Thanks a lot. > > -Alex >> >> -Alex >> >>> Is it possible that there is some sort of deadlock going on? We are >>> doing the rbd maps (and subsequent filesystem mounts) on the same >>> systems which are running the ceph-osd and ceph-mon processes. To get >>> around the 'sync' deadlock problem, we are using a patch from Sage >>> which ignores system wide sync's on filesystems mounted with the >>> 'mand' option (and we mount the underlying osd filesystems with >>> 'mand'). However I am wondering if there is potential for other types >>> of deadlocks in this environment. >>> >>> Also, we recently saw an rbd hang in a much older version, running >>> kernel 3.5.3 with only the sync hack patch, along side ceph 0.48.1. >>> It's possible that this issue was around for some time, just the >>> recent patches made it happen more often (and thus more reproducible) >>> for us. >>> >>> >>> On Tue, Dec 18, 2012 at 8:09 AM, Alex Elder <elder@xxxxxxxxxxx> wrote: >>>> On 12/17/2012 11:12 AM, Nick Bartos wrote: >>>>> Here's a log with the rbd debugging enabled: >>>>> >>>>> https://gist.github.com/raw/4319962/d9690fd92c169198efc5eecabf275ef1808929d2/rbd-hang-test-1355763470.log >>>>> >>>>> On Fri, Dec 14, 2012 at 10:03 AM, Alex Elder <elder@xxxxxxxxxxx> wrote: >>>>>> On 12/14/2012 10:53 AM, Nick Bartos wrote: >>>>>>> Yes I was only enabling debugging for libceph. I'm adding debugging >>>>>>> for rbd as well. I'll do a repro later today when a test cluster >>>>>>> opens up. >>>>>> >>>>>> Excellent, thank you. -Alex >>>> >>>> I looked through these debugging messages. Looking only at the >>>> rbd debugging, what I see seems to indicate that rbd is idle at >>>> the point the "hang" seems to start. This suggests that the hang >>>> is not due to rbd itself, but rather whatever it is that might >>>> be responsible for using the rbd image once it has been mapped. >>>> >>>> Is that possible? I don't know what process you have that is >>>> mapping the rbd image, and what is supposed to be the next thing >>>> it does. (I realize this may not make a lot of sense, given >>>> a patch in rdb seems to have caused the hang to begin occurring.) >>>> >>>> Also note that the debugging information available (i.e., the >>>> lines in the code that can output debugging information) may >>>> well be incomplete. So if you don't find anything it may be >>>> necessary to provide you with another update which might include >>>> more debugging. >>>> >>>> Anyway, could you provide a little more context about what >>>> is going on sort of *around* rbd when activity seems to stop? >>>> >>>> Thanks a lot. >>>> >>>> -Alex >> > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
