From: Martin <m_btrfs@ml1.co.uk>
To: linux-btrfs@vger.kernel.org
Subject: Re: What to do about snapshot-aware defrag
Date: Wed, 04 Jun 2014 00:54:14 +0100 [thread overview]
Message-ID: <lmln77$ee0$1@ger.gmane.org> (raw)
In-Reply-To: <538C7A79.8070407@fb.com>
On 02/06/14 14:22, Josef Bacik wrote:
> On 05/30/2014 06:00 PM, Martin wrote:
>> 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.
[...]
>> 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?
>>
>
> Yeah atime would screw this up, I hadn't thought of that. With that
> being the case I think the only option is to keep the old behavior, we
> don't want to screw up stuff like this just because users used a backup
> program on their snapshot and didn't use noatime. Thanks,
Not so fast into non-KISS!
The *ONLY* application that I know of that uses atime is Mutt and then
*only* for mbox files!...
NOTHING else uses atime as far as I know.
We already have most distros enabling reltime by default as a
just-in-case...
Can we not have noatime as the default for btrfs? Also widely note that
default in the man page and wiki and with why?...
*And go KISS and move on faster* better?
Myself, I still use Mutt sometimes, but no mbox, and all my filesystems
have been noatime for many years now with good positive results. (Both
home and work servers.)
Regards,
Martin
next prev parent reply other threads:[~2014-06-03 23:54 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
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 [this message]
2014-06-04 9:19 ` Erkki Seppala
2014-06-04 13:15 ` Martin
2014-06-04 19:33 ` Chris Murphy
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