Hugo Mills - 15.10.18, 16:26:
> On Mon, Oct 15, 2018 at 05:24:08PM +0300, Anton Shepelev wrote:
> > Hello, all
> >
> > While trying to resolve free space problems, and found that
> >
> > I cannot interpret the output of:
> > > btrfs filesystem show
> >
> > Label: none uuid: 8971ce5b-71d9-4e46-ab25-ca37485784c8
> > Total devices 1 FS bytes used 34.06GiB
> > devid 1 size 40.00GiB used 37.82GiB path /dev/sda2
> >
> > How come the total used value is less than the value listed
> > for the only device?
>
> "Used" on the device is the mount of space allocated. "Used" on the
> FS is the total amount of actual data and metadata in that
> allocation.
>
> You will also need to look at the output of "btrfs fi df" to see
> the breakdown of the 37.82 GiB into data, metadata and currently
> unused.
I usually use btrfs fi usage -T, cause
1. It has all the information.
2. It differentiates between used and allocated.
% btrfs fi usage -T /
Overall:
Device size: 100.00GiB
Device allocated: 54.06GiB
Device unallocated: 45.94GiB
Device missing: 0.00B
Used: 46.24GiB
Free (estimated): 25.58GiB (min: 25.58GiB)
Data ratio: 2.00
Metadata ratio: 2.00
Global reserve: 70.91MiB (used: 0.00B)
Data Metadata System
Id Path RAID1 RAID1 RAID1 Unallocated
-- ------------------------ -------- --------- -------- -----------
2 /dev/mapper/msata-debian 25.00GiB 2.00GiB 32.00MiB 22.97GiB
1 /dev/mapper/sata-debian 25.00GiB 2.00GiB 32.00MiB 22.97GiB
-- ------------------------ -------- --------- -------- -----------
Total 25.00GiB 2.00GiB 32.00MiB 45.94GiB
Used 22.38GiB 754.66MiB 16.00KiB
For RAID it in some place reports the raw size and sometimes the logical
size. Especially in the "Total" line I find this a bit inconsistent.
"RAID1" columns show logical size, "Unallocated" shows raw size.
Also "Used:" in the global section shows raw size and "Free
(estimated):" shows logical size.
Thanks
--
Martin
