Re: Kernel 5.4 - BTRFS FS shows full with about 600 GB Free ?

Swâmi Petaramesh
2019-12-22T10:17:07Z

Le 22/12/2019 à 10:37, Qu Wenruo a écrit :
>>
>> With « uncommitted metadata » do you mean that this situation is only
>> temporary and should end once all transactions are commited to disk ?
>
> Yes. The temporary part also matches with one kind reporter's description.
> So for that v5.4 temporary 0 available, it should be the case.

Unfortunately in my case it was not « temporary », the filesystem was
idle, and the « zero free space » survived unmounts and remounts and
showed the same using kernels 5.3 and 4.15 on other machines...

...But a « btrfs balance -m » (under kernel 5.4) fixed it in the end.

> But there is one valid behavior which may cause such 0 available space
> situation.
> Are you using RAID1 or RAID10 with hugely unbalanced disk size?

Absolutely not. Relatively fresh BTRFS FS on a single 2TB device on
which at least 33% of the space had never been allocated.

> We need extra info to further determine the cause of the persistent 0
> available space problem.
> `btrfs fi usage` output would help a lot.

Here's all what I get AFTER the "btrfs balance -m" fixed things:

[moksha /]# uname -r
5.4.2-1-MANJARO

[moksha /]# btrfs fi sh
Label: 'MyFS' uuid: xxxxxxxxx-yyyy-zzzz-tttt-wwwwwwwwwwww
Total devices 1 FS bytes used 1.19TiB
devid 1 size 1.82TiB used 1.20TiB path
/dev/mapper/luks-aaaaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee

[moksha /]# btrfs fi df /run/media/myself/MyFS
Data, single: total=1.18TiB, used=1.18TiB
System, DUP: total=32.00MiB, used=160.00KiB
Metadata, DUP: total=8.00GiB, used=6.93GiB
GlobalReserve, single: total=512.00MiB, used=0.00B

[moksha /]# btrfs fi us /run/media/myself/MyFS
Overall:
Device size: 1.82TiB
Device allocated: 1.20TiB
Device unallocated: 633.90GiB
Device missing: 0.00B
Used: 1.20TiB
Free (estimated): 634.26GiB (min: 317.31GiB)
Data ratio: 1.00
Metadata ratio: 2.00
Global reserve: 512.00MiB (used: 0.00B)

Data,single: Size:1.18TiB, Used:1.18TiB (99.97%)
/dev/mapper/luks-aaaaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee 1.18TiB

Metadata,DUP: Size:8.00GiB, Used:6.93GiB (86.63%)
/dev/mapper/luks-aaaaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee 16.00GiB

System,DUP: Size:32.00MiB, Used:160.00KiB (0.49%)
/dev/mapper/luks-aaaaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee 64.00MiB

Unallocated:
/dev/mapper/luks-aaaaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee 633.90GiB

[moksha /]# df -h /run/media/myself/MyFS
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/luks-aaaaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee 1,9T 1,2T
635G 66% /run/media/myself/MyFS

ॐ
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