Hi, I was rsyncing some 54 GB onto a newly created btrfs filesystem, both metadata and data in RAID1 and using lzo compression, when after transferring less than half of the amount rsync stopped with "no space left on device", while the destination filesystem was less than half filled. I started rsync again shortly afterwards and it finished the copy without further problems. The filesystem is doing just fine now, there were no errors logged to syslog, I don''t know whether this is reproducible (didn''t try), but, as I am AFAIK using the newest version of the software involved, I send this mail just to say: It is still possible to get an unwarranted ENOSPC with btrfs. Please see below for the details. Thanks for working on btrfs! Regards, Lutz Kernel: v3.3-rc1-383-g0a96265 uname -a: Linux test 3.3.0-rc1 #1 SMP PREEMPT Sun Jan 29 16:06:29 CET 2012 x86_64 x86_64 x86_64 GNU/Linux btrfs-progs: cloned on 2012-01-25 from git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-progs.git, latest commit is fdb6c0402337d9607c7a39155088eaf033742752. OS: Ubuntu 11.04. The source filesystem is ext4 on an SSD. The destination is another SSD (sdb), partitioned into 2 x 40 GB. The filesystem was created like so: # mkfs.btrfs -d raid1 -m raid1 /dev/sdb1 /dev/sdb2 # btrfs device scan I made an entry in /etc/fstab: UUID=88af7576-3027-4a3b-a5ae-34bfd167982f /mnt btrfs compress=lzo 0 0 # mount /mnt # grep sdb /proc/mounts /dev/sdb1 /mnt btrfs rw,relatime,compress=lzo,ssd,space_cache 0 0 The rsync call was: $ time rsync -ax --delete test /mnt After 17 minutes rsync stopped with "No space left on device", but there was still lots of space: $ df -h /mnt Dateisystem Size Used Avail Use% Eingehängt auf /dev/sdb1 75G 31G 42G 43% /mnt # btrfs fi show /dev/sdb1 Label: none uuid: 88af7576-3027-4a3b-a5ae-34bfd167982f Total devices 2 FS bytes used 15.47GB devid 2 size 37.26GB used 21.01GB path /dev/sdb2 devid 1 size 37.26GB used 21.03GB path /dev/sdb1 I issued the same rsync call a few minutes later and after another 17 minutes it finished successfully. The filesystem is still not full: $ df -h /mnt Dateisystem Size Used Avail Use% Eingehängt auf /dev/sdb1 75G 62G 12G 85% /mnt # btrfs fi show /dev/sdb1 Label: none uuid: 88af7576-3027-4a3b-a5ae-34bfd167982f Total devices 2 FS bytes used 30.92GB devid 2 size 37.26GB used 37.25GB path /dev/sdb2 devid 1 size 37.26GB used 37.26GB path /dev/sdb1 $ du -sh /mnt 54G /mnt -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html