From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o4JBk9c1126179 for ; Wed, 19 May 2010 06:46:09 -0500 Received: from bombadil.infradead.org (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 603E41DF3242 for ; Wed, 19 May 2010 04:48:28 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org [18.85.46.34]) by cuda.sgi.com with ESMTP id L6iccW2gaSGNOPPL for ; Wed, 19 May 2010 04:48:28 -0700 (PDT) Date: Wed, 19 May 2010 07:48:26 -0400 From: Christoph Hellwig Subject: Re: XFS on 2.6.26: reading the first 4K of a large file takes ages Message-ID: <20100519114826.GA18224@infradead.org> References: <8239xojfco.fsf@mid.bfk.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <8239xojfco.fsf@mid.bfk.de> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Florian Weimer Cc: xfs@oss.sgi.com On Wed, May 19, 2010 at 11:33:27AM +0000, Florian Weimer wrote: > We've got a couple of rather large files, and with a cold cache, > reading the first 4K bytes of the file (e.g., just running > "head --bytes 4096" on it) takes ages, up to several minutes, > sometimes triggering the hang check timer. > > I wonder if XFS reads the whole extent information into RAM when the > file is opened. Is this the case, at least on 2.6.26? Has this > changed in later versions, perhaps? Yes, XFS always reads in the extent map, and no this hasn't changed recently. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs