Hi guys, I am running into really bad performance. Here's my setup: WD Red 6 TB connected over USB2 to my core i7 laptop, running Ubuntu 32-bit with kernel 4.0.4-040004-generic #201505171336.
Single btrfs partition covering whole disk. Autodefrag is on. fstab line: UUID=... /media/X btrfs rw,nosuid,nodev,autodefrag 0 0 Sometimes when files are being modified or removed, I see btrfs-transacti eat 100% cpu; during this time no io operations succeed, that is, they're all stalled. You can't even ls on that fs. This happens for several minutes then normal operation resumes. There doesn't seem to be a rule to what will trigger this, other than opening a single file and reading usually works quite well. (say, watching a movie while all other programs are closed). But even moving files off the disks triggers some sort of bug. Just now I am moving a few files (just 30gb worth) onto another disk, and the bug triggers. So btrfs-transacti was eating my cpu for over 5 minutes and according to mv's output after this was done and cpu usage went back to normal what I was waiting for was for a tiny png file to be removed. This is pretty bad. I have tried defragmenting directories where files are being accessed and moved. This hasn't helped. This happens whether the FS is near full or not. It currently is near full but it wasn't before and it still did that. It still has about ~ 100GB free space now. The more things are happening the more often this bug gets triggered. So if I have utorrent running and its temporary downloads directory is there, its download speed graph will be a few spikes of running at several MB/sec separated by durations of 0 download speed. Nothing seems to show up in dmesg or syslog. I have asked in #btrfs but the suggestions ended up not fixing the issue (autodefrag, defrag dirs). Please advise what I should do with this issue. -- 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
