From: Julien Muchembled <jm@jmuchemb.eu>
To: Chris Mason <clm@fb.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: kernel >= 3.16 saturates I/O endlessly and without reason
Date: Tue, 11 Nov 2014 22:05:55 +0100 [thread overview]
Message-ID: <54627A33.90202@jmuchemb.eu> (raw)
In-Reply-To: <1415737858.25389.0@mail.thefacebook.com>
Le 11/11/14 21:30, Chris Mason a écrit :
> On Tue, Nov 11, 2014 at 3:10 PM, Julien Muchembled <jm@jmuchemb.eu> wrote:
>> I upgraded my kernel from 3.15.10 to 3.17.2 and after a while, btrfs kworkers started to read/write data at maximum speed for hours whereas I was doing nothing. So I rebooted with kernel 3.15.10 and hopefully everything went back to normal. Later attempts to upgrade to 3.16.7 or 3.17.2 showed the same issue, immediately at boot or after a while.
>>
>> In order to investigate a little, I copied the partition and mounted it in qemu (snapshot mode, with cow file in tmpfs, debian kernel 3.16.7-2). I could see that btrfs always wrote the same ~8MB in loop. qemu used all cpu and when I stopped it, it wrote 190G and the generation number raised from 625955 to 853922.
>>
>> I dumped the FS with btrfs-image. The restored FS has the same issue so I can send the image (78M) to anyone who would like to debug.
>
> Which mount options are you using? This sounds like something in autodefrag...
I've never used autodefrag.
In qemu, I did:
mount -t btrfs -o noatime /dev/sda /mnt/sda
prev parent reply other threads:[~2014-11-11 21:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-11 20:10 kernel >= 3.16 saturates I/O endlessly and without reason Julien Muchembled
2014-11-11 20:30 ` Chris Mason
2014-11-11 21:05 ` Julien Muchembled [this message]
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