On 2017-01-28 13:15, MegaBrutal wrote:
Hello,Of course I can't retrieve the data from before the balance, but here is the data from now: root@vmhost:~# btrfs fi show /tmp/mnt/curlybrace Label: 'curlybrace' uuid: f471bfca-51c4-4e44-ac72-c6cd9ccaf535 Total devices 1 FS bytes used 752.38MiB devid 1 size 2.00GiB used 1.90GiB path /dev/mapper/vmdata--vg-lxc--curlybrace root@vmhost:~# btrfs fi df /tmp/mnt/curlybrace Data, single: total=773.62MiB, used=714.82MiB System, DUP: total=8.00MiB, used=16.00KiB Metadata, DUP: total=577.50MiB, used=37.55MiB GlobalReserve, single: total=512.00MiB, used=0.00B root@vmhost:~# btrfs fi usage /tmp/mnt/curlybrace Overall: Device size: 2.00GiB Device allocated: 1.90GiB Device unallocated: 103.38MiB Device missing: 0.00B Used: 789.94MiB Free (estimated): 162.18MiB (min: 110.50MiB) Data ratio: 1.00 Metadata ratio: 2.00 Global reserve: 512.00MiB (used: 0.00B) Data,single: Size:773.62MiB, Used:714.82MiB /dev/mapper/vmdata--vg-lxc--curlybrace 773.62MiB Metadata,DUP: Size:577.50MiB, Used:37.55MiB /dev/mapper/vmdata--vg-lxc--curlybrace 1.13GiB System,DUP: Size:8.00MiB, Used:16.00KiB /dev/mapper/vmdata--vg-lxc--curlybrace 16.00MiB Unallocated: /dev/mapper/vmdata--vg-lxc--curlybrace 103.38MiB So... if I sum the data, metadata, and the global reserve, I see why only ~170 MB is left. I have no idea, however, why the global reserve sneaked up to 512 MB for such a small file system, and how could I resolve this situation. Any ideas? MegaBrutal
Total amateur here just jumping in, so feel free to ignore me, but what caught my eye was the small device size.
I've had issues with BTRFS on small devices (4GiB & 8GiB), forcing me to use other filesystems on them (like EXT4, which has a smaller allocation size). Issues being both ENOSPC and miscellaneous other strange errors (which may have been fixed by now).
My theory being that the 1GiB data and 256MiB metadata chunk sizes are significant on such small devices.
I don't know if there is an official recommended minimum device size, but keeping 4GiB or more free seems to work most of the time for my usage patterns.
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