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
