From: Martin <m_btrfs@ml1.co.uk>
To: linux-btrfs@vger.kernel.org
Subject: Re: What to do about snapshot-aware defrag
Date: Fri, 30 May 2014 23:00:24 +0100 [thread overview]
Message-ID: <lmav1p$ih7$1@ger.gmane.org> (raw)
In-Reply-To: <5388ED6B.8000706@fb.com>
OK... I'll jump in...
On 30/05/14 21:43, Josef Bacik wrote:
> Hello,
>
> TL;DR: I want to only do snapshot-aware defrag on inodes in snapshots
> that haven't changed since the snapshot was taken. Yay or nay (with a
> reason why for nay)
[...]
>
> === Summary and what I need ===
>
> Option 1: Only relink inodes that haven't changed since the snapshot was
> taken.
>
> Pros:
> -Faster
> -Simpler
> -Less duplicated code, uses existing functions for tricky operations so
> less likely to introduce weird bugs.
>
> Cons:
> -Could possibly lost some of the snapshot-awareness of the defrag. If
> you just touch a file we would not do the relinking and you'd end up
> with twice the space usage.
[...]
Obvious way to go for fast KISS.
One question:
Will option one mean that we always need to mount with noatime or
read-only to allow snapshot defragging to do anything?
Regards,
Martin
next prev parent reply other threads:[~2014-05-30 22:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-30 20:43 What to do about snapshot-aware defrag Josef Bacik
2014-05-30 22:00 ` Martin [this message]
2014-05-31 23:51 ` Brendan Hide
2014-06-01 1:52 ` Duncan
2014-06-02 3:07 ` Mitch Harder
2014-06-02 13:19 ` Josef Bacik
2014-06-02 13:22 ` Josef Bacik
2014-06-03 23:54 ` Martin
2014-06-04 9:19 ` Erkki Seppala
2014-06-04 13:15 ` Martin
2014-06-04 19:33 ` Chris Murphy
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