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From: Eric Sandeen <sandeen@redhat.com>
To: Ron Yorston <rmy@tigress.co.uk>
Cc: xfs@oss.sgi.com, linux-ext4@vger.kernel.org
Subject: Re: sparsify - utility to punch out blocks of 0s in a file
Date: Sun, 05 Feb 2012 10:36:39 -0600	[thread overview]
Message-ID: <4F2EB017.5090006@redhat.com> (raw)
In-Reply-To: <201202050933.q159XQpB026380@helium.internal.tigress.co.uk>

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?)
> 
> Way ahead of you.  I wrote my sparsify utility for ext2 in 2004:
> 
>    http://intgat.tigress.co.uk/rmy/uml/sparsify.html

Cool, I had not known about that one.  But that one is a bit less generic -
ext2-specific and requiring an unmounted fs, right?

> It's mostly of historical interest now, I suppose.  The sparsify utility
> doesn't work on ext4 and I long since gave up maintaining the kernel
> patch.  I still use the zerofree utility, though.
> 
> It would be nice to have a modern version of sparsify.  I'll try it out.

Thanks!

Matthias' suggestion of adding SEEK_HOLE/SEEK_DATA makes very good sense too.
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...

-Eric
 
> Ron


WARNING: multiple messages have this Message-ID (diff)
From: Eric Sandeen <sandeen@redhat.com>
To: Ron Yorston <rmy@tigress.co.uk>
Cc: linux-ext4@vger.kernel.org, xfs@oss.sgi.com
Subject: Re: sparsify - utility to punch out blocks of 0s in a file
Date: Sun, 05 Feb 2012 10:36:39 -0600	[thread overview]
Message-ID: <4F2EB017.5090006@redhat.com> (raw)
In-Reply-To: <201202050933.q159XQpB026380@helium.internal.tigress.co.uk>

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?)
> 
> Way ahead of you.  I wrote my sparsify utility for ext2 in 2004:
> 
>    http://intgat.tigress.co.uk/rmy/uml/sparsify.html

Cool, I had not known about that one.  But that one is a bit less generic -
ext2-specific and requiring an unmounted fs, right?

> It's mostly of historical interest now, I suppose.  The sparsify utility
> doesn't work on ext4 and I long since gave up maintaining the kernel
> patch.  I still use the zerofree utility, though.
> 
> It would be nice to have a modern version of sparsify.  I'll try it out.

Thanks!

Matthias' suggestion of adding SEEK_HOLE/SEEK_DATA makes very good sense too.
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...

-Eric
 
> Ron

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  reply	other threads:[~2012-02-05 16:36 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 [this message]
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
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

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