From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o4JBVBT1125389 for ; Wed, 19 May 2010 06:31:12 -0500 Received: from mx01.bfk.de (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 10C28359A51 for ; Wed, 19 May 2010 04:33:29 -0700 (PDT) Received: from mx01.bfk.de (mx01.bfk.de [193.227.124.2]) by cuda.sgi.com with ESMTP id CTyIOlhjnq5gttgn for ; Wed, 19 May 2010 04:33:29 -0700 (PDT) Received: from mx00.int.bfk.de ([10.119.110.2]) by mx01.bfk.de with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) id 1OEhWe-0003hk-GR for xfs@oss.sgi.com; Wed, 19 May 2010 11:33:24 +0000 Received: by bfk.de with local id 1OEhWh-0001SN-C7 for xfs@oss.sgi.com; Wed, 19 May 2010 11:33:27 +0000 Subject: XFS on 2.6.26: reading the first 4K of a large file takes ages From: Florian Weimer Date: Wed, 19 May 2010 11:33:27 +0000 Message-ID: <8239xojfco.fsf@mid.bfk.de> MIME-Version: 1.0 List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com 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? The files in question are heavily fragmented (they have been created with holes first, and the holes have been filled in subsequently). I'll try to run xfs_fsr on those files, but it's going to be tough. 8-/ -- = Florian Weimer BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstra=DFe 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs