From: "Jörn Engel" <joern@wohnheim.fh-wedel.de>
To: Andy Isaacson <adi@hexapodia.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Is there a "make hole" (truncate in middle) syscall?
Date: Fri, 12 Dec 2003 17:03:25 +0100 [thread overview]
Message-ID: <20031212160325.GI6112@wohnheim.fh-wedel.de> (raw)
In-Reply-To: <20031212094031.B1303@hexapodia.org>
On Fri, 12 December 2003 09:40:31 -0600, Andy Isaacson wrote:
>
> A related idea was reportedly used in the Venti filesystem, which was
> discussed on linux-kernel back in October; look for the thread
> "Transparent compression in the FS".
>
> The downsides are pretty substantial (but the upsides are too). You
> don't know how many blocks are available on the filesystem for you to
> write, because when you write you might not allocate blocks. And you
> lose disk-streaming-perfomance, because you're going to be seeking all
> over the disk picking up the blocks for your files.
Right - to some degree. I'm sure many problems can be dealt with, but
it takes a lot of time to sort out the details. For streaming
performance, I guess in most cases you will get the same performance
because you won't find a single duplicate block in those files. Two
competing readers should be a much bigger problem.
Still, there are more problems, no doubt.
> > But we should get there some day. Having 15 nearly identical copies
> > of the kernel on my notebook is a pain and hard links simply have the
> > wrong semantics.
>
> I don't know about you, but I don't have 15 nearly identical copies of
> the kernel; I have 30 copies that have almost no text in common, and
> certainly have no blocks in common -- they result from independent
> compilations, and the resulting bzImage files are not duplicates.
s/kernel/kernel source/
If it was just the images, I couldn't care less. But 15x 200-300 Megs
does hurt a bit. :)
grep -r over multiple trees hurts even more, when RAM spills over.
Jörn
--
And spam is a useful source of entropy for /dev/random too!
-- Jasmine Strong
next prev parent reply other threads:[~2003-12-12 16:03 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-04 20:32 Is there a "make hole" (truncate in middle) syscall? Rob Landley
2003-12-04 20:55 ` Måns Rullgård
2003-12-04 21:10 ` Szakacsits Szabolcs
2003-12-05 0:02 ` Rob Landley
2003-12-04 22:33 ` Szakacsits Szabolcs
2003-12-05 11:22 ` Helge Hafting
2003-12-05 12:11 ` Måns Rullgård
2003-12-05 22:41 ` Mike Fedyk
2003-12-05 23:25 ` Måns Rullgård
2003-12-05 23:33 ` Szakacsits Szabolcs
2003-12-05 23:25 ` Szakacsits Szabolcs
2003-12-04 21:48 ` Mike Fedyk
2003-12-04 23:59 ` Rob Landley
2003-12-05 22:42 ` Olaf Titz
2003-12-04 22:53 ` Peter Chubb
2003-12-05 1:04 ` Philippe Troin
2003-12-05 2:39 ` Peter Chubb
2003-12-08 4:03 ` bill davidsen
2003-12-04 23:23 ` Andy Isaacson
2003-12-04 23:42 ` Szakacsits Szabolcs
2003-12-05 2:03 ` Mike Fedyk
2003-12-05 7:09 ` Ville Herva
2003-12-05 11:22 ` Anton Altaparmakov
2003-12-05 11:44 ` viro
2003-12-05 14:27 ` Anton Altaparmakov
2003-12-05 21:00 ` sparse file performance (was Re: Is there a "make hole" (truncate in middle) syscall?) Andy Isaacson
2003-12-05 21:12 ` Linus Torvalds
2003-12-08 20:43 ` Andy Isaacson
2003-12-11 5:13 ` Is there a "make hole" (truncate in middle) syscall? Hua Zhong
2003-12-11 6:19 ` Rob Landley
2003-12-11 18:58 ` Andy Isaacson
2003-12-11 19:15 ` Hua Zhong
2003-12-11 19:43 ` Andreas Dilger
2003-12-12 21:37 ` Daniel Phillips
2003-12-11 19:48 ` Jörn Engel
2003-12-11 19:55 ` Hua Zhong
2003-12-11 19:58 ` Andy Isaacson
2003-12-12 12:18 ` Jörn Engel
2003-12-12 15:40 ` Andy Isaacson
2003-12-12 16:03 ` Jörn Engel [this message]
2003-12-11 20:32 ` Rob Landley
2003-12-12 12:55 ` Jörn Engel
2003-12-12 13:28 ` Vladimir Saveliev
2003-12-12 13:43 ` Jörn Engel
2003-12-12 13:52 ` Vladimir Saveliev
2003-12-12 14:04 ` Jörn Engel
2003-12-12 13:53 ` Rob Landley
2003-12-12 14:01 ` Vladimir Saveliev
2003-12-12 21:35 ` Rob Landley
2003-12-15 10:00 ` Vladimir Saveliev
2003-12-15 11:52 ` Rob Landley
2003-12-15 13:26 ` Jörn Engel
2003-12-12 13:39 ` Rob Landley
2003-12-12 13:56 ` Jörn Engel
2003-12-12 14:24 ` Jörn Engel
2003-12-12 21:37 ` Rob Landley
2003-12-15 12:47 ` Jörn Engel
2003-12-16 5:43 ` Rob Landley
2003-12-16 11:05 ` Jörn Engel
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