From: Duncan <1i5t5.duncan@cox.net>
To: linux-btrfs@vger.kernel.org
Subject: Re: Btrfs-progs-3.16: fs metadata is both single and dup?
Date: Wed, 3 Sep 2014 04:53:39 +0000 (UTC) [thread overview]
Message-ID: <pan$5f385$eac97af1$e9cf0e10$15446dc8@cox.net> (raw)
In-Reply-To: 20140902121349.GF18897@carfax.org.uk
Hugo Mills posted on Tue, 02 Sep 2014 13:13:49 +0100 as excerpted:
> On Tue, Sep 02, 2014 at 12:05:33PM +0000, Holger Hoffstätte wrote:
>>
>> I updated to progs-3.16 and noticed during testing:
>> root>mkfs.btrfs -f /dev/loop0
>> All fine until here..
>>
>> root>btrfs filesystem df /tmp/btrfs
>> Data, single: total=8.00MiB, used=64.00KiB
>> System, DUP: total=8.00MiB, used=16.00KiB
>> System, single: total=4.00MiB, used=0.00
>> Metadata, DUP: total=409.56MiB, used=112.00KiB
>> Metadata, single: total=8.00MiB, used=0.00
>
> Note that the "single" chunks are empty, and will remain so.
>
>> So where does the confusing initial display come from? [I] don't
>> remember ever seeing this with btrfs-progs-3.14.2.
>
> Your memory is faulty, I'm afraid. It's always done that -- at
> least since I started using btrfs, several years ago.
>
> I believe it comes from mkfs creating a trivial basic filesystem
> (with the single profiles), and then setting enough flags on it that the
> kernel can bootstrap it with the desired chunks in it -- but I may be
> wrong about that.
Agreed. It's an artifact of the mkfs.btrfs process and a btrfs fi df on
a new filesystem always seems to have those extra unused single profile
lines.
I got so the first thing I'd do on first mount was a balance -- before
there was anything actually on the filesystem so it was real fast -- to
get rid of those null entries.
Actually, I had already created a little mkfs.btrfs helper script that
sets options I normally want, etc, and after doing the mkfs and balance
drill a few times, I setup the script such that if at the appropriate
prompt I give it a mountpoint to point balance at, it'll mount the
filesystem and immediately run a balance, thus automating things and
making the balance part of the same scripted process that does the
mkfs.btrfs in the first place.
IOW, those null-entry lines bother me too... enough that even tho I know
what they are I arranged things so they're automatically and immediately
eliminated and I don't have to see 'em! =:^)
--
Duncan - List replies preferred. No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master." Richard Stallman
next prev parent reply other threads:[~2014-09-03 4:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-02 12:05 Btrfs-progs-3.16: fs metadata is both single and dup? Holger Hoffstätte
2014-09-02 12:13 ` Hugo Mills
2014-09-02 12:34 ` Holger Hoffstätte
2014-09-03 4:53 ` Duncan [this message]
2014-09-03 7:33 ` Hugo Mills
2014-09-03 8:41 ` Duncan
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