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From: Martin <m_btrfs@ml1.co.uk>
To: linux-btrfs@vger.kernel.org
Subject: Re: Suggestion: Anti-fragmentation safety catch (RFC)
Date: Tue, 25 Mar 2014 00:57:05 +0000	[thread overview]
Message-ID: <lgqk8i$j4p$1@ger.gmane.org> (raw)
In-Reply-To: <pan$191e5$f5ca4422$3e26f4d9$15d09a73@cox.net>

On 24/03/14 20:19, Duncan wrote:
> Martin posted on Mon, 24 Mar 2014 19:47:34 +0000 as excerpted:
> 
>> Possible fix:
>>
>> btrfs checks the ratio of filesize versus number of fragments and for a
>> bad ratio either: [...]
> 
>> 3: Automatically defragments the file.
> 
> See the autodefrag mount option.
> 
> =:^)

Thanks for that!

So...

https://btrfs.wiki.kernel.org/index.php/Mount_options
####
autodefrag (since [kernel] 3.0)

Will detect random writes into existing files and kick off background
defragging. It is well suited to bdb or sqlite databases, but not
virtualization images or big databases (yet). Once the developers make
sure it doesn't defrag files over and over again, they'll move this
toward the default.
####

Looks like I might be a good test case :-)


What's the problem for big images or big databases? What is considered
"big"?

Thanks,
Martin


  reply	other threads:[~2014-03-25  0:57 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-24 19:47 Suggestion: Anti-fragmentation safety catch (RFC) Martin
2014-03-24 20:19 ` Duncan
2014-03-25  0:57   ` Martin [this message]
2014-03-25 15:42     ` Duncan

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