Hi, 1 février 2016 20:42 "Eric Wheeler" <bcache@xxxxxxxxxxxxxxxxxx> a écrit: > [ changed subject, more below ] > Are you using md-based raid5/raid6? Not at all. In my setup Bcache is used on two bare drives (HDD and SSD) behing a hardware RAID controller (disks configured in non-RAID mode). > > If so, it could be the raid_partial_stripes_expensive bug. > > If it *is* the bcache optimizations around partial_stripes_expensive, then > please try the patch below and then do this *before* loading the bcache > module (or at least before registering the bcache backing volume): > echo 0 > /sys/block/BLK/queue/limits/raid_partial_stripes_expensive > where BLK is your backing volume. > > I wrote this patch because we use hardware RAID5/6 and wanted to get the > partial_stripes_expensive optimizations on by setting > raid_partial_stripes_expensive=1 and io_opt=our_stride_width. > Unfortunately it caused the backtrace in the LKML thread below, so we > stopped using it. > > See also this thread, however, it shows a backtrace prior to > removing the bio splitting code: > https://lkml.org/lkml/2016/1/7/844 I'll take a look. > Note that commit 749b61dab30736eb95b1ee23738cae90973d4fc3 might not > exactly address this issue, but it might prevent full hangs. Make sure > you cherry-pick commit 749b61dab30736eb95b1ee23738cae90973d4fc3 and > hand-clean-up as necessary. It simplifies the bio code and deletes a bunch > of stuff. It showed up in 4.4 and isn't in my patchset. > > After commit the commit above and setting > raid_partial_stripes_expensive=1 > we still get errors like this: > bcache: bch_count_io_errors() dm-3: IO error on writing data to cache, > recovering but they don't lock up the system. Ultimately we run with > raid_partial_stripes_expensive=0 because of these related problemsand > haven't had any issues. Also, fwiw, we run 4.1.y as our stable branch > backed by hardware raid. I'll give a try if find some time to do so. Thks. -- Open is better -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
