Hi Sage, I did some testing with btrfs-unstable yesterday. With the recent commit from Chris it looks quite good: "Btrfs: force unplugs when switching from high to regular priority bios" However I can't test it extensively, because our main environment is on ext4 at the moment. Regards Christian 2011/8/8 Sage Weil <sage@xxxxxxxxxxxx>: > Hi Christian, > > Are you still seeing this slowness? > > sage > > > On Wed, 27 Jul 2011, Christian Brunner wrote: >> 2011/7/25 Chris Mason <chris.mason@xxxxxxxxxx>: >> > Excerpts from Christian Brunner's message of 2011-07-25 03:54:47 -0400: >> >> Hi, >> >> >> >> we are running a ceph cluster with btrfs as it's base filesystem >> >> (kernel 3.0). At the beginning everything worked very well, but after >> >> a few days (2-3) things are getting very slow. >> >> >> >> When I look at the object store servers I see heavy disk-i/o on the >> >> btrfs filesystems (disk utilization is between 60% and 100%). I also >> >> did some tracing on the Cepp-Object-Store-Daemon, but I'm quite >> >> certain, that the majority of the disk I/O is not caused by ceph or >> >> any other userland process. >> >> >> >> When reboot the system(s) the problems go away for another 2-3 days, >> >> but after that, it starts again. I'm not sure if the problem is >> >> related to the kernel warning I've reported last week. At least there >> >> is no temporal relationship between the warning and the slowdown. >> >> >> >> Any hints on how to trace this would be welcome. >> > >> > The easiest way to trace this is with latencytop. >> > >> > Apply this patch: >> > >> > http://oss.oracle.com/~mason/latencytop.patch >> > >> > And then use latencytop -c for a few minutes while the system is slow. >> > Send the output here and hopefully we'll be able to figure it out. >> >> I've now installed latencytop. Attached are two output files: The >> first is from yesterday and was created aproxematly half an hour after >> the boot. The second on is from today, uptime is 19h. The load on the >> system is already rising. Disk utilization is approximately at 50%. >> >> Thanks for your help. >> >> Christian >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- 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
