Here's a log with a hang on the updated branch: https://gist.github.com/raw/4381750/772476e1bae1e6366347a223f34aa6c440b92765/rdb-hang-1356543132.log On Thu, Dec 20, 2012 at 1:59 PM, Alex Elder <elder@xxxxxxxxxxx> wrote: > On 12/20/2012 11:48 AM, Nick Bartos wrote: >> Unfortunately, we still have a hang: >> >> https://gist.github.com/4347052/download > > The saga continues, and each time we get a little more > information. Please try branch: "wip-nick-newerest" > > Thank you. > > -Alex > > >> 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
