Well, since we're on the topic, my backup server btrfs FS has become so slow that it hangs my system a few seconds here and there and causes some of my cron jobs to fail.
I'm going to re-create it for a 3 time (in 3 years), adding bcache this time, but clearly there is a good chance that this filesystem is indeed going to crap performance wise because all it does is receive btrfs receive and rsync backups, with snapshot rotations (daily snapshots, and they expire after a couple of weeks). I'm currently doing a very slow defrag to see if it'll help (looks like it's going to take days). I'm doing this: for i in dir1 dir2 debian32 debian64 ubuntu dir4 ; do echo $i; time btrfs fi defragment -v -r $i; done But, just to be clear, is there a way I missed to see how fragmented my filesystem is without running filefrag on millions of files and parsing the output? Label: 'dshelf2' uuid: d4a51178-c1e6-4219-95ab-5c5864695bfd Total devices 1 FS bytes used 4.25TiB devid 1 size 7.28TiB used 4.44TiB path /dev/mapper/dshelf2 btrfs fi df /mnt/btrfs_pool2/ Data, single: total=4.29TiB, used=4.18TiB System, DUP: total=64.00MiB, used=512.00KiB Metadata, DUP: total=77.50GiB, used=73.31GiB GlobalReserve, single: total=512.00MiB, used=31.22MiB Currently, it's btrfs on top of dmcrpyt on top of swraid5 Since I'm about to recreate this after a very slow backup/restore process, if you have suggestions on how I could better build this (outside of using a 4.4 kernel this time), they would be appreciated. Also, should I try running defragment -r from cron from time to time? Thanks, Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/ | PGP 1024R/763BE901 -- 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