From: Eric Sandeen <sandeen@redhat.com>
To: Andreas Dilger <adilger@dilger.ca>
Cc: Ron Yorston <rmy@tigress.co.uk>,
"xfs@oss.sgi.com" <xfs@oss.sgi.com>,
"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
Subject: Re: sparsify - utility to punch out blocks of 0s in a file
Date: Sun, 05 Feb 2012 11:23:21 -0600 [thread overview]
Message-ID: <4F2EBB09.6080905@redhat.com> (raw)
In-Reply-To: <9C5B5C07-B0E4-4D13-BCFE-7F35162DF5E8@dilger.ca>
On 2/5/12 10:55 AM, Andreas Dilger wrote:
> On 2012-02-05, at 9:36, Eric Sandeen <sandeen@redhat.com> wrote:
>> On 2/5/12 3:33 AM, Ron Yorston wrote:
>>> Eric Sandeen wrote:
>>>> Now that ext4, xfs, & ocfs2 can support punch hole, a tool to
>>>> "re-sparsify" a file by punching out ranges of 0s might be in order.
>>>>
>>>> I'll see if util-linux wants it after it gets beat into shape.
>>>> (or did a tool like this already exist and I missed it?)
>>
>> Matthias' suggestion of adding SEEK_HOLE/SEEK_DATA makes very good sense too.
>
> I thought about this, but if SEEK_HOLE/SEEK_DATA (or FIEMAP) worked,
> then the file would already be sparse, so I don't think that will
> help in this case...
But only if other tools originally used them, and there will probably be plenty
of cases where they don't, or legacy files, or ....
>> I should also untie the read/zero buffer size from the minimum hole size,
>> we should do optimal IO sizes regardless of the minimum hole size desired...
>
> Definitely. 4kB IO is a killer for large files.
yeah, it was a quick hack, I'll try to fix that up.
(OTOH for large files you man not want a 4k hole granularity either)
-Eric
> Cheers, Andreas
WARNING: multiple messages have this Message-ID (diff)
From: Eric Sandeen <sandeen@redhat.com>
To: Andreas Dilger <adilger@dilger.ca>
Cc: "linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
Ron Yorston <rmy@tigress.co.uk>,
"xfs@oss.sgi.com" <xfs@oss.sgi.com>
Subject: Re: sparsify - utility to punch out blocks of 0s in a file
Date: Sun, 05 Feb 2012 11:23:21 -0600 [thread overview]
Message-ID: <4F2EBB09.6080905@redhat.com> (raw)
In-Reply-To: <9C5B5C07-B0E4-4D13-BCFE-7F35162DF5E8@dilger.ca>
On 2/5/12 10:55 AM, Andreas Dilger wrote:
> On 2012-02-05, at 9:36, Eric Sandeen <sandeen@redhat.com> wrote:
>> On 2/5/12 3:33 AM, Ron Yorston wrote:
>>> Eric Sandeen wrote:
>>>> Now that ext4, xfs, & ocfs2 can support punch hole, a tool to
>>>> "re-sparsify" a file by punching out ranges of 0s might be in order.
>>>>
>>>> I'll see if util-linux wants it after it gets beat into shape.
>>>> (or did a tool like this already exist and I missed it?)
>>
>> Matthias' suggestion of adding SEEK_HOLE/SEEK_DATA makes very good sense too.
>
> I thought about this, but if SEEK_HOLE/SEEK_DATA (or FIEMAP) worked,
> then the file would already be sparse, so I don't think that will
> help in this case...
But only if other tools originally used them, and there will probably be plenty
of cases where they don't, or legacy files, or ....
>> I should also untie the read/zero buffer size from the minimum hole size,
>> we should do optimal IO sizes regardless of the minimum hole size desired...
>
> Definitely. 4kB IO is a killer for large files.
yeah, it was a quick hack, I'll try to fix that up.
(OTOH for large files you man not want a 4k hole granularity either)
-Eric
> Cheers, Andreas
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2012-02-05 17:23 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-04 20:04 sparsify - utility to punch out blocks of 0s in a file Eric Sandeen
2012-02-04 20:04 ` Eric Sandeen
2012-02-04 20:10 ` Eric Sandeen
2012-02-04 20:10 ` Eric Sandeen
2012-02-04 20:17 ` Eric Sandeen
2012-02-04 20:17 ` Eric Sandeen
2012-02-05 15:05 ` Raghavendra D Prabhu
2012-02-05 15:05 ` Raghavendra D Prabhu
2012-02-05 23:44 ` Michael Tokarev
2012-02-05 23:44 ` Michael Tokarev
2012-02-05 23:55 ` Eric Sandeen
2012-02-05 23:55 ` Eric Sandeen
2012-02-05 9:33 ` Ron Yorston
2012-02-05 9:33 ` Ron Yorston
2012-02-05 16:36 ` Eric Sandeen
2012-02-05 16:36 ` Eric Sandeen
2012-02-05 16:55 ` Andreas Dilger
2012-02-05 16:55 ` Andreas Dilger
2012-02-05 17:23 ` Matthias Schniedermeyer
2012-02-05 17:23 ` Eric Sandeen [this message]
2012-02-05 17:23 ` Eric Sandeen
2012-02-05 19:24 ` Andreas Dilger
2012-02-05 19:24 ` Andreas Dilger
2012-02-05 17:19 ` Ron Yorston
2012-02-05 17:19 ` Ron Yorston
2012-02-05 17:21 ` Eric Sandeen
2012-02-05 17:21 ` Eric Sandeen
2012-02-06 18:40 ` Sunil Mushran
2012-02-06 18:40 ` [Ocfs2-devel] " Sunil Mushran
2012-02-06 18:40 ` Sunil Mushran
2012-02-06 21:41 ` Ted Ts'o
2012-02-06 21:41 ` Ted Ts'o
2012-02-06 21:47 ` Eric Sandeen
2012-02-06 21:47 ` Eric Sandeen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4F2EBB09.6080905@redhat.com \
--to=sandeen@redhat.com \
--cc=adilger@dilger.ca \
--cc=linux-ext4@vger.kernel.org \
--cc=rmy@tigress.co.uk \
--cc=xfs@oss.sgi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.