Re: extremely slow syncing on btrfs with 2.6.39.1
On 07/11/2011 02:18 AM, Kok, Auke-jan H wrote: > I've been monitoring the lists for a while now but didn't see this > problem mentioned in particular: I've got a fairly standard desktop > system at home, 700gb WD drive, nothing special, with 2 btrfs > filesystems and some snapshots. The system runs for days, and I've > noticed unusual disk activity the other evening - turns out that it's > taking forever to sync(). > > $ uname -r > 2.6.39.1 > $ grep btrfs /proc/mounts > /dev/root / btrfs rw,relatime 0 0# is /dev/sdb2 # > /dev/sdb5 /home btrfs rw,relatime 0 0 > $ time sync > > real 1m5.552s > user 0m0.000s > sys 0m2.102s > > $ time sync > > real 1m16.830s > user 0m0.001s > sys 0m1.490s > > $ df -h / /home > Filesystem Size Used Avail Use% Mounted on > /dev/root47G 33G 7.7G 82% / > /dev/sdb5 652G 216G 421G 34% /home > $ btrfs fi df / > Data: total=35.48GB, used=29.86GB > System, DUP: total=16.00MB, used=12.00KB > System: total=4.00MB, used=0.00 > Metadata, DUP: total=4.50GB, used=1.67GB > $ btrfs fi df /home > Data: total=310.01GB, used=209.53GB > System, DUP: total=8.00MB, used=48.00KB > System: total=4.00MB, used=0.00 > Metadata, DUP: total=11.00GB, used=2.98GB > Metadata: total=8.00MB, used=0.00 > > I'll switch to 3.0 soon, but, given the fact that we're going to be > running MeeGo on 2.6.39 probably for a while, I was wondering if > anyone knows off the top of their heads if this issue is > known/identified. If not then I'll need to make someone do some > patching ;). > > Auke You should read the thread "Abysmal Performance" of these mailing list from last month. They had a similar problem and downgraded to a 2.6.38 kernel. By the way, that works for me too for the time being. Best Regards. Jan Stilow -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Applications using fsync cause hangs for several seconds every few minutes
Hello, Nirbheek Chauhan gentoo.org> writes: > However, recently, perhaps with 2.6.39, or after I quickly started > filling up my disk again, it has become impossible for me to work for > long periods on my machine. > > Every few minutes, (I guess) when applications do fsync (firefox, > xchat, vim, etc), all applications that use fsync() hang for several > seconds, and applications that use general IO suffer extreme > slowdowns. iotop shows various combinations of the processes listed > below doing writes, and the total write as 2-3MB/s. > > [btrfs-dealloc-] > [btrfs-submit-0] > [btrfs-transacti] > [btrfs-endio-wri] > [flush-btrfs-1] I'm using btrfs under a 2.6.39-ARCH kernel and run into the same issue. In my case the [btrfs-submit-0] and [btrfs-transacti] shows up in iotop and produce 99% of IO at the time a application is frozen. For something like 10 to 30 seconds. After a fresh boot everything runs quiet acceptable and goes worse over the day. If I reboot the unmount process takes a lot of time something up to 8 minutes. After the reboot everything is back to normal. At least for a while. I use snapshots on a daily base and have 20 active snapshots all the time. Maybe this is the reason for the performance impact? > What can I do to debug this issue? What other information should I > supply? Could someone guide me on how to figure out why my machine is > unusable now? I have no solution for this problem. In fact a reboot helps me even if only temporary. I also changed the IO scheduler, switched to laptop mode and remounted the device. Neither of these helped. Maybe someone else has any suggestion? Thanks. Jan Stilow -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
