Re: very poor ext3 write performance on big filesystems?

From: Chris Mason <chris.mason@oracle.com>
To: Tomasz Chmielewski <mangoo@wpkg.org>
Cc: Theodore Tso <tytso@mit.edu>, Andi Kleen <andi@firstfloor.org>,
	LKML <linux-fsdevel@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: very poor ext3 write performance on big filesystems?
Date: Tue, 19 Feb 2008 10:06:50 -0500	[thread overview]
Message-ID: <200802191006.50693.chris.mason@oracle.com> (raw)
In-Reply-To: <47BAED94.3040103@wpkg.org>

On Tuesday 19 February 2008, Tomasz Chmielewski wrote:
> Theodore Tso schrieb:
>
> (...)
>
> > The following ld_preload can help in some cases.  Mutt has this hack
> > encoded in for maildir directories, which helps.
>
> It doesn't work very reliable for me.
>
> For some reason, it hangs for me sometimes (doesn't remove any files, rm
> -rf just stalls), or segfaults.

You can go the low-tech route (assuming your file names don't have spaces in 
them)

find . -printf "%i %p\n" | sort -n | awk '{print $2}' | xargs rm

>
>
> As most of the ideas here in this thread assume (re)creating a new
> filesystem from scratch - would perhaps playing with
> /proc/sys/vm/dirty_ratio and /proc/sys/vm/dirty_background_ratio help a
> bit?

Probably not.  You're seeking between all the inodes on the box, and probably 
not bound by the memory used.

-chris