From: ching <lsching17@gmail.com>
To: linux-btrfs@vger.kernel.org
Subject: Re: enquiry about defrag
Date: Wed, 12 Sep 2012 07:33:02 +0800 [thread overview]
Message-ID: <504FCA2E.90906@gmail.com> (raw)
In-Reply-To: <20120911114559.GV17430@twin.jikos.cz>
On 09/11/2012 07:45 PM, David Sterba wrote:
> On Tue, Sep 11, 2012 at 07:12:58PM +0800, ching wrote:
>>> 1. According to btrfs wiki, defragment a COW file will produce two unrelated files.
>>>
>>> Does it apply to the "autodefrag" mount option?
>> can anybody helps on question 1?
> The data blocks associated with the files (that were originally created
> by snapshotting and thus shared the same blocks) will become unshared,
> so yes it would appear like two unlreated files.
>
> Autodefrag option affects only newly written data. With current
> implementation it could unshare some extents if the defragged range
> picked by autodefrag logic overlaps with an existing one.
>
> >From my experience, running 'btrfs fi defrag' with autodefrag on
> produced better result. Beware that there are some unfixed deadlocks
> that may happen with autodefrag enabled.
>
> david
>
thanks for your help very much :)
prev parent reply other threads:[~2012-09-11 23:33 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-09 0:03 enquiry about defrag ching
2012-09-09 0:30 ` Jan Steffens
2012-09-09 7:49 ` ching
2012-09-09 9:11 ` Fajar A. Nugraha
2012-09-09 12:05 ` ching
2012-09-10 12:19 ` ching
2012-09-10 13:10 ` Liu Bo
2012-09-10 23:21 ` ching
2012-09-11 1:28 ` Li Zefan
2012-09-11 11:12 ` ching
2012-09-10 9:23 ` Alex Lyakas
2012-09-11 11:12 ` ching
2012-09-11 11:45 ` David Sterba
2012-09-11 23:33 ` ching [this message]
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