From: Marc MERLIN <marc@merlins.org>
To: Andrei Borzenkov <arvidjaar@gmail.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: How to find/reclaim missing space in volume
Date: Mon, 5 Jun 2023 18:46:36 -0700 [thread overview]
Message-ID: <20230606014636.GG105809@merlins.org> (raw)
In-Reply-To: <9bfa8bb6-b64e-d34f-f9c8-db5f9510fc29@gmail.com>
On Mon, Jun 05, 2023 at 08:00:02PM +0300, Andrei Borzenkov wrote:
> On 05.06.2023 19:26, Marc MERLIN wrote:
> > I have this:
> > sauron [mc]# df -h .
> > Filesystem Size Used Avail Use% Mounted on
> > /dev/mapper/pool2 1.1T 853G 212G 81% /mnt/btrfs_pool2
> > sauron [mc]# btrfs fi show .
> > Label: 'btrfs_pool2' uuid: fde3da31-67e9-4f88-b90d-6c3f6becd56a
> > Total devices 1 FS bytes used 847.89GiB
> > devid 1 size 1.04TiB used 890.02GiB path /dev/mapper/pool2
> > sauron [mc]# btrfs fi df .
> > Data, single: total=878.00GiB, used=843.85GiB
> > System, DUP: total=8.00MiB, used=128.00KiB
> > Metadata, DUP: total=6.00GiB, used=4.04GiB
> > GlobalReserve, single: total=512.00MiB, used=0.00B
> >
>
> btrfs filesystem usage -T is usually more useful than both the above
> commands.
sauron:/mnt/btrfs_pool2# btrfs fi usage -T .
Overall:
Device size: 1.04TiB
Device allocated: 890.02GiB
Device unallocated: 177.73GiB
Device missing: 0.00B
Used: 851.85GiB
Free (estimated): 211.93GiB (min: 123.07GiB)
Data ratio: 1.00
Metadata ratio: 2.00
Global reserve: 512.00MiB (used: 0.00B)
Data Metadata System
Id Path single DUP DUP Unallocated
-- ----------------- --------- -------- --------- -----------
1 /dev/mapper/pool2 878.00GiB 12.00GiB 16.00MiB 177.73GiB
-- ----------------- --------- -------- --------- -----------
Total 878.00GiB 6.00GiB 8.00MiB 177.73GiB
Used 843.79GiB 4.03GiB 128.00KiB
> > sauron:/mnt/btrfs_pool2# du -sh *
> > 599G varchange2
> > 598G varchange2_ggm_daily_ro.20230605_07:57:43
> > 4.0K varchange2_last
> > 599G varchange2_ro.20230605_08:01:30
> > 599G varchange2_ro.20230605_09:01:43
> >
> > I'm confused, the volumes above are snapshots with mostly the same data
> > (made within the last 2 hours) and I didn't delete any data in the FS
> > (they are mostly identical and used for btfrs send/receive)
> >
> > Why do they add up ot 600GB, but btrfs says 847FB is used?
> >
>
> Each subvolume references 600G but it does not mean they are the same 600G.
> If quota is enabled, "btrfs quota show" may provide some more information,
> otherwise "btrfs filesystem du" shows shared and exclusive space (you need
> to pass all subvolumes in question to correctly compute shared vs
> exclusive).
Right, I did check/know that the snapshots shared the same data, but it
doens't hurt to confirm:
sauron:/mnt/btrfs_pool2# btrfs filesystem du -s *
Total Exclusive Set shared Filename
597.57GiB 20.00KiB 588.75GiB varchange2
597.57GiB 4.00KiB 588.75GiB varchange2_ggm_daily_ro.20230605_09:59:26
597.57GiB 0.00B 588.75GiB varchange2_last
597.57GiB 4.00KiB 588.75GiB varchange2_minly.20230605_17:30:33
597.57GiB 0.00B 588.75GiB varchange2_minly.20230605_17:35:32
597.57GiB 0.00B 588.75GiB varchange2_minly.20230605_17:40:32
597.57GiB 4.00KiB 588.75GiB varchange2_minly.20230605_17:45:32
597.57GiB 4.00KiB 588.75GiB varchange2_minly.20230605_17:50:32
597.57GiB 4.00KiB 588.75GiB varchange2_minly.20230605_17:55:32
597.57GiB 0.00B 588.75GiB varchange2_minly.20230605_18:00:32
597.57GiB 0.00B 588.75GiB varchange2_minly.20230605_18:05:32
597.57GiB 8.00KiB 588.75GiB varchange2_minly.20230605_18:10:32
597.57GiB 16.00KiB 588.75GiB varchange2_ro.20230605_10:01:40
597.57GiB 12.00KiB 588.75GiB varchange2_ro.20230605_11:01:31
597.57GiB 4.00KiB 588.75GiB varchange2_ro.20230605_13:01:28
597.57GiB 4.00KiB 588.75GiB varchange2_ro.20230605_14:01:30
597.57GiB 4.00KiB 588.75GiB varchange2_ro.20230605_15:01:29
597.57GiB 4.00KiB 588.75GiB varchange2_ro.20230605_16:01:32
597.57GiB 4.00KiB 588.75GiB varchange2_ro.20230605_17:01:31
597.57GiB 0.00B 588.75GiB varchange2_ro.20230605_18:02:02
sauron:/mnt/btrfs_pool2# df -h .
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/pool2 1.1T 853G 212G 81% /mnt/btrfs_pool2
--
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Home page: http://marc.merlins.org/ | PGP 7F55D5F27AAF9D08
next prev parent reply other threads:[~2023-06-06 1:46 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-05 16:26 How to find/reclaim missing space in volume Marc MERLIN
2023-06-05 16:47 ` Roman Mamedov
2023-06-05 17:00 ` Andrei Borzenkov
2023-06-06 1:46 ` Marc MERLIN [this message]
2023-06-06 4:47 ` Andrei Borzenkov
2023-06-06 16:41 ` Marc MERLIN
2023-06-06 18:25 ` Roman Mamedov
2023-06-07 2:12 ` Qu Wenruo
2023-06-07 19:17 ` Marc MERLIN
2023-06-07 19:32 ` Hans van Kranenburg
2023-06-07 20:02 ` Marc MERLIN
2023-06-07 20:31 ` Hans van Kranenburg
2023-06-06 18:19 ` Graham Cobb
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