This is an interesting case. My readynas reported overnight that it was critically short on storage of the root partition. After SSHing inot the box, I could not find any large files. The system was surprisingly fast--the GUI seemed fine on multiple PCs and responsive to requests to update users, turn off apps, etc. Thus I thought it may be a false positive. So after meating my head against the wall, i decided to reboot--knowing that there was a chance the GUI would not come up and i would need to use the command line to figure out what is going on.
However, It came back up at 47%--which is the standard for me. (Yes, I realize that is high for some, but i have alot of stuff added on and i have moved all writing off the root drive to ensure very little else is written to it. Virtualbox, emacs and others take up some space)
This was a happy ending to something that would have been tragic! All i can think is that a job i set to export a OVA in virtualbox accidentally may have been written to /root vs /data. I found it in the default virtualbox folder unfinished (root parition). But deleting the partial file did not help. Could it be some of the temp files for this 7 GB file were stuck somewhere or the system pre-allocated space for the files before they write written?
Could it be some of the temp files for this 7 GB file were stuck somewhere or the system pre-allocated space for the files before they write written?
The root file system on the x86 NAS is btrfs (like the data volume). So it is possible that the file system became fully allocated.
You might want to do a btrfs fi df // and compare total with used. The difference is the amount of partially allocated chunks. Doing a balance of the root with btrfs balance start //can reduce that difference. You'll get a warning about how long it might take, which you can ignore (the filesystem is small, so it won't really take very long).
Here's a sample from my RN526. You'll see the balance freed up about 400 MB of allocated space (10% of the root partition).
# btrfs fi df //
Data, single: total=1.62GiB, used=986.55MiB
System, DUP: total=32.00MiB, used=16.00KiB
Metadata, DUP: total=128.00MiB, used=12.41MiB
GlobalReserve, single: total=16.00MiB, used=0.00B
# btrfs balance start //
WARNING:
Full balance without filters requested. This operation is very
intense and takes potentially very long. It is recommended to
use the balance filters to narrow down the scope of balance.
Use 'btrfs balance start --full-balance' option to skip this
warning. The operation will start in 10 seconds.
Use Ctrl-C to stop it.
10 9 8 7 6 5 4 3 2 1
Starting balance without any filters.
Done, had to relocate 6 out of 6 chunks
# btrfs fi df //
Data, single: total=1.22GiB, used=986.76MiB
System, DUP: total=32.00MiB, used=16.00KiB
Metadata, DUP: total=128.00MiB, used=12.53MiB
GlobalReserve, single: total=16.00MiB, used=0.00B
If you do run out of space during the balance, you can try again with filters (-dlimit and/or -dusage).
