On Sun, Apr 28, 2013 at 9:18 PM, John . <btrfsprob@xxxxxxxxx> wrote: > I use Ubuntu with kernel 3.8.0-19-generic. I also tested with the > latest live disk of Arch Linux; write performance was the same (bad). > > My mount options: rw,compress=lzo. > Iotop does not show any strange disk activity. > > 2013/4/28 Harald Glatt <mail@xxxxxxxxx>: >> On Sun, Apr 28, 2013 at 9:10 PM, John . <btrfsprob@xxxxxxxxx> wrote: >>> Hi Harald, >>> >>> I did perform a defrag of the volume a few hours ago. This did not >>> make a difference. :( >>> >>> Yours, >>> >>> John >>> >>> 2013/4/28 Harald Glatt <mail@xxxxxxxxx>: >>>> On Sun, Apr 28, 2013 at 9:04 PM, John . <btrfsprob@xxxxxxxxx> wrote: >>>>> Hi guys, >>>>> >>>>> My Btrfs fs has a performance problem which I hope you can help me >>>>> solve. I have a dataset of around 3.15 TiB, that has lived on a ZFS >>>>> volume for almost two years (ZRAID1, 4 2TiB disks). In order to move >>>>> to Btrfs I bought myself a 4TiB disk with the idea of buying a new one >>>>> next week and balance it to a RAID1 of 2 4TiB disks. >>>>> >>>>> I created a single disk Btrfs volume with the default mkfs options (no >>>>> data duplication, metadata duplication on). Next I transferred my >>>>> dataset to this disk (no problems there). Today when I tried to create >>>>> a directory and I noticed the Btrfs volume was awefully slow; it took >>>>> a few seconds to create the directory and a few to delete it (which >>>>> should be milliseconds as you know). In fact each and every operation >>>>> on the volume grinded the fs down to a halt. >>>>> >>>>> FS information: >>>>> >>>>> # btrfs fi df /storage >>>>> Data: total=3.29TB, used=3.15TB >>>>> System, DUP: total=8.00MB, used=360.00KB >>>>> System: total=4.00MB, used=0.00 >>>>> Metadata, DUP: total=4.00GB, used=3.88GB >>>>> Metadata: total=8.00MB, used=0.00 >>>>> >>>>> # btrfs fi show >>>>> Label: 'storage' uuid: 3fa262cd-baa9-46dc-92a8-318c87166186 >>>>> Total devices 1 FS bytes used 3.16TB >>>>> devid 1 size 3.64TB used 3.30TB path /dev/sdb >>>>> >>>>> I suspect my performance blow has everything to do with the abysmally >>>>> low amount of space for metadata that is left, but since I am not a >>>>> Btrfs guru I don't now whether this is truly the case and/or how to >>>>> solve it. btrfs fi balance start -dusage=5 did not help. >>>>> >>>>> Yours, >>>>> >>>>> John >>>>> -- >>>>> 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 >>>> >>>> Try to defragment the root of the volume (e.g the mountpoint). While >>>> it's mounted: >>>> btrfs fi defrag /path/to/mnt >>>> >>>> Then try performance again >> >> What kernel version do you use? What are your mount options? Try to >> run iotop and see if there is any unusual activity... Try mount -o inode_cache,space_cache,autodefrag - first mount with the new options might take a while, also there might be disk activity for a while after mounting with this... -- 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
