From: Andrei Borzenkov <arvidjaar@gmail.com>
To: Qu Wenruo <quwenruo.btrfs@gmx.com>,
"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: Confused by btrfs quota group accounting
Date: Sun, 23 Jun 2019 16:42:13 +0300 [thread overview]
Message-ID: <63286845-0fc3-e595-3e35-e8e2bef4fd17@gmail.com> (raw)
In-Reply-To: <2c0e3d7e-9b7d-dde8-c4f3-2ca89071efbf@gmx.com>
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23.06.2019 14:29, Qu Wenruo пишет:
>
>
> BTW, so many fragmented extents, this normally means your system has
> very high memory pressure or lack of memory, or lack of on-disk space.
It is 1GiB QEMU VM with vanilla Tumbleweed with GNOME desktop; nothing
runs except user GNOME session. Does it fit "high memory pressure"
definition?
> Above 100MiB should be in one large extent, not split into so many small
> ones.
>
OK, so this is where I was confused. I was sure that filefrag returns
true "physical" extent layout. It seems that in filefrag output
consecutive extents are merged giving false picture of large extent
instead of many small ones. Filefrag shows 5 ~200MiB extents, not over
30 smaller ones.
Is it how generic IOCTL is designed to work or is it something that
btrfs does internally? This *is* confusing.
In any case, thank you for clarification, this makes sense now.
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next prev parent reply other threads:[~2019-06-23 13:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-22 15:11 Confused by btrfs quota group accounting Andrei Borzenkov
2019-06-23 7:55 ` Qu Wenruo
2019-06-23 8:08 ` Qu Wenruo
2019-06-23 10:15 ` Andrei Borzenkov
2019-06-23 11:29 ` Qu Wenruo
2019-06-23 13:42 ` Andrei Borzenkov [this message]
2019-06-23 13:55 ` Qu Wenruo
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