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From: Szakacsits Szabolcs <szaka@sienet.hu>
To: Matthew Wilcox <matthew@wil.cx>
Cc: linux-fsdevel@vger.kernel.org
Subject: Re: Efficient handling of sparse files
Date: Mon, 28 Feb 2005 19:57:57 +0100 (MET)	[thread overview]
Message-ID: <Pine.LNX.4.21.0502281944170.3541-100000@mlf.linux.rulez.org> (raw)
In-Reply-To: <20050228174149.GA28741@parcelfarce.linux.theplanet.co.uk>


On Mon, 28 Feb 2005, Matthew Wilcox wrote:

> This problem came up with the systemimager program which uses rsync to
> install files from a master server to many clients.  Red Hat has a system
> user with uid 2^32-1 which causes lastlog to grow to 1.2GB in size.
> rsync does understand the concept of sparse files (with the -S flag), but
> it has to read every block to discover that it is indeed empty.  This sucks.

XFS supports what you want. I made a related benchmark some years ago, if
you are interested,

	http://marc.theaimsgroup.com/?l=reiserfs&m=105827549109079
 
> I was wondering if we could introduce a new system call (or ioctl?) that,
> given an fd would find the next block with data in it.  

I think, this is a bad idea. The XFS or the NTFS interface could be a
better start.

	Szaka


  parent reply	other threads:[~2005-02-28 18:58 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-02-28 17:41 Efficient handling of sparse files Matthew Wilcox
2005-02-28 17:44 ` Jeremy Allison
2005-02-28 20:13   ` Bryan Henderson
2005-02-28 21:49     ` Jamie Lokier
2005-03-01 18:37       ` Bryan Henderson
2005-02-28 18:57 ` Szakacsits Szabolcs [this message]
2005-02-28 19:55 ` Zach Brown
2005-02-28 20:40 ` Anton Altaparmakov
2005-02-28 20:53   ` Zach Brown
2005-03-01  7:50     ` Anton Altaparmakov

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