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From: Tomasz Chmielewski <mangoo@wpkg.org>
To: Stephane Chazelas <stephane_chazelas@yahoo.fr>
Cc: linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: curious writes on mounted, not used btrfs filesystem
Date: Sun, 22 May 2011 11:52:37 +0200	[thread overview]
Message-ID: <4DD8DCE5.6070703@wpkg.org> (raw)
In-Reply-To: <20110522093352.GA22491@yahoo.fr>

On 22.05.2011 11:34, Stephane Chazelas wrote:
> 2011-05-21 14:58:21 +0200, Tomasz Chmielewski:
>> I have a btrfs filesystem (2.6.39) which is mounted, but otherwise, not used:
>>
>> # lsof -n|grep /mnt/btrfs
>
> processes with open fds are one thing. You could also have loop
> devices setup on it for instance.

I know.
It's _not_ used by anything.


>> #
>>
>>
>> I noticed that whenever I do "sync", btrfs will write for around 6.5s and write 13 MB (see below).
> [...]
>
> You could try and play with /proc/sys/vm/block_dump to see what
> is being written (remember to disable logging of kernel messages
> by syslog).

It doesn't give me any hints, really.


Can you try running these commands yourself:

iostat -k 1 </your/btrfs/device>


And in a second terminal:

while true; do sync ; done


To see if your btrfs makes writes on sync each time?


-- 
Tomasz Chmielewski
http://wpkg.org

  reply	other threads:[~2011-05-22  9:52 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-21 12:58 curious writes on mounted, not used btrfs filesystem Tomasz Chmielewski
2011-05-22  9:34 ` Stephane Chazelas
2011-05-22  9:52   ` Tomasz Chmielewski [this message]
2011-05-22 18:26     ` Stephane Chazelas
2011-05-22 15:21   ` Swâmi Petaramesh

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