Forum Discussion

Aspirant

Nov 03, 2017

BTRFS is killing my NAS

I'm having major issues with btrfs in ReadyNAS. Every once in a while it just kills my NAS to a point where even typing SSH commands is very sluggish. Web UI and shares are not accessible. I've read ...

Performance

mdgm-ntgr

NETGEAR Employee Retired

Nov 04, 2017

Which firmware are you running?

Have you disabled quotas at the volume level?

How full is your data volume?

anserk

Aspirant

Nov 04, 2017

I'm running 6.8.1. I never enabled quota but reading forums it seems like it might have been enabled automatically by a certain firmware update. As part of the troubleshooting (and desperation), I pulled the plug and was able to log in via SSH, which was responsive despite btrfs-transacti process starting to eat up CPU. I had pulled the plug before - the system usually worked for a few minutes before stalling again. So this time I immediately issued this:

btrfs quota disable /data

It's been 15 minutes so far and I don't see any btrfs activity - all services are available.

Now that I can actually access the system, I looked at the GUI logs. The last entry is from snapshot prune worker from 11/2 23:19, the next message is from today when I restarted it. Logs in journalctl indicate there was an out of memory condition around that same time.

Here the output of some btrfs commands.

btrfs fi df /data
Data, single: total=3.84TiB, used=3.47TiB
System, DUP: total=32.00MiB, used=672.00KiB
Metadata, DUP: total=3.00GiB, used=1.74GiB
GlobalReserve, single: total=485.88MiB, used=2.91MiB
root@NAS:~# btrfs fi show
Label: '0e35c581:data'  uuid: 07dfdef1-b26e-474a-b2ca-42a55738cb01
        Total devices 1 FS bytes used 3.47TiB
        devid    1 size 4.54TiB used 3.85TiB path /dev/md127
root@NAS:~# df -h /data
Filesystem      Size  Used Avail Use% Mounted on
/dev/md127      4.6T  3.5T  1.1T  76% /data

What is the best approach now to do any necessary btrfs maintenance? I had a monthly defrag which I disabled for now. I'm afraid to run balance as I had bad experience with it in the past (system locks up).

mdgm-ntgr
NETGEAR Employee Retired
Nov 05, 2017
There is a GUI option to disable volume quotas and also an OS Re-install will disable volume quotas.

Volume maintenance should be scheduled during times where the NAS is being used lightly. Likewise with backups (obviously at a different time to volume maintenance).

Your volume usage is approaching the point where it would be a good idea to free up some space or expand the volume.
- DonOKeeffe
  Aspirant
  Feb 05, 2018
  results of btrfs filesystem df /Volume1
  
  root@VegaNAS:~# btrfs filesystem df /Volume1
  Data, single: total=2.68TiB, used=2.67TiB
  System, DUP: total=32.00MiB, used=352.00KiB
  Metadata, DUP: total=49.50GiB, used=33.51GiB
  GlobalReserve, single: total=512.00MiB, used=200.03MiB
  - StephenB
    Guru - Experienced User
    Feb 05, 2018
    wrote:
    
    results of btrfs filesystem df /Volume1
    
    root@VegaNAS:~# btrfs filesystem df /Volume1
    Data, single: total=2.68TiB, used=2.67TiB
    System, DUP: total=32.00MiB, used=352.00KiB
    Metadata, DUP: total=49.50GiB, used=33.51GiB
    GlobalReserve, single: total=512.00MiB, used=200.03MiB
    
    Which shows it as being completely full - which is not good.
    
    But what does running the same command on // tell you about the OS partition???