From: Martin Steigerwald <martin@lichtvoll.de>
To: Hugo Mills <hugo@carfax.org.uk>,
Anton Shepelev <anton.txt@gmail.com>,
linux-btrfs@vger.kernel.org
Subject: Re: Interpreting `btrfs filesystem show'
Date: Mon, 15 Oct 2018 17:48:15 +0200 [thread overview]
Message-ID: <20001436.sb0dmY2reh@merkaba> (raw)
In-Reply-To: <20181015142641.GD9538@carfax.org.uk>
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
prev parent reply other threads:[~2018-10-15 15:48 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-15 14:24 Interpreting `btrfs filesystem show' Anton Shepelev
2018-10-15 14:26 ` Hugo Mills
2018-10-15 14:30 ` Hugo Mills
[not found] ` <20181015174040.6f4962336386d8549026908c@gmail.com>
2018-10-15 14:42 ` Anton Shepelev
2018-10-15 15:02 ` Austin S. Hemmelgarn
2018-10-15 15:48 ` Martin Steigerwald [this message]
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