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... -- 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
