u/CreativeGPX

Edit: It appears I was stuck because every time I tried to mount a balance that I had tried restarted which locked the drive because it didn't have enough room to proceed. I solved this by unmounting, then remounting with -o skip_balance. From there I deleted a file and then added a device and rebalanced to get some breathing room.

Just created a new BTRFS volume comprised of a 1TB and 2TB drive in RAID1 for both metadata and data. It has no snapshots and 7 subvolumes, some directories are compressed but not most.

From what I can tell it went read-only because I filled it. I don't know how to actually fix that though because when it's read-only I can't free up space on it.

sudo dmesg | grep -i btrfs:

[102895.930974] BTRFS: error (device sdi1 state A) in btrfs_run_delayed_refs:2247: errno=-28 No space left
[102895.930978] BTRFS info (device sdi1 state EA): forced readonly
[102895.931491] BTRFS info (device sdi1 state EA): 2 enospc errors during balance
[102895.931495] BTRFS info (device sdi1 state EA): balance: ended with status: -30

sudo btrfs fi show /mnt/betterStorage/:

Label: 'BetterStorage'  uuid: 79f9a7ca-e97b-461c-9123-c62b39b52661
	Total devices 2 FS bytes used 930.59GiB
	devid    1 size 1.82TiB used 931.51GiB path /dev/sdi1
	devid    2 size 931.51GiB used 931.51GiB path /dev/sda1

sudo btrfs device stats /mnt/betterStorage/:

[/dev/sdi1].write_io_errs    0
[/dev/sdi1].read_io_errs     0
[/dev/sdi1].flush_io_errs    0
[/dev/sdi1].corruption_errs  0
[/dev/sdi1].generation_errs  0
[/dev/sda1].write_io_errs    0
[/dev/sda1].read_io_errs     0
[/dev/sda1].flush_io_errs    0
[/dev/sda1].corruption_errs  0
[/dev/sda1].generation_errs  0

So, how do I resolve this issue?

---

Second Question

The above commands seem to indicate that it's full, but in Btrfs Assistant it says:

Filesystem Size: 2.73TiB
Allocated: 1.82TiB (66.67%)
Used: 1.82TiB (66.60%)
Free (Estimated): 466.30 GiB (16.69%)
Free (Minimum): 466.30 GiB (16.69%)
You have lots of free space, did you overbuy?

Is Btrfs Assistant just wrong or are these numbers saying something different than I think? Because it's presented as though I have free space which is why I didn't realize I filled it up at first.

It looks like that's pulling from the following from the command line:

sudo btrfs fi us -T /mnt/betterStorage:

Overall:
    Device size:		   2.73TiB
    Device allocated:		   1.82TiB
    Device unallocated:		 931.51GiB
    Device missing:		     0.00B
    Device slack:		   6.00KiB
    Used:			   1.82TiB
    Free (estimated):		 466.30GiB	(min: 466.30GiB)
    Free (statfs, df):		 557.80MiB
    Data ratio:			      2.00
    Metadata ratio:		      2.00
    Global reserve:		 512.00MiB	(used: 0.00B)
    Multiple profiles:		        no

             Data      Metadata System                                 
Id Path      RAID1     RAID1    RAID1     Unallocated Total     Slack  
-- --------- --------- -------- --------- ----------- --------- -------
 1 /dev/sdi1 929.48GiB  2.00GiB  32.00MiB   931.50GiB   1.82TiB 3.00KiB
 2 /dev/sda1 929.48GiB  2.00GiB  32.00MiB     1.04MiB 931.51GiB 3.00KiB
-- --------- --------- -------- --------- ----------- --------- -------
   Total     929.48GiB  2.00GiB  32.00MiB   931.51GiB   2.73TiB 6.00KiB
   Used      928.94GiB  1.66GiB 144.00KiB