From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o4L6f3of252400 for ; Fri, 21 May 2010 01:41:04 -0500 Received: from mx01.bfk.de (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 70756A0378B for ; Thu, 20 May 2010 23:44:39 -0700 (PDT) Received: from mx01.bfk.de (mx01.bfk.de [193.227.124.2]) by cuda.sgi.com with ESMTP id WD4uvHmOAWFXXQI2 for ; Thu, 20 May 2010 23:44:39 -0700 (PDT) Subject: Re: XFS on 2.6.26: reading the first 4K of a large file takes ages References: <8239xojfco.fsf@mid.bfk.de> <20100519114826.GA18224@infradead.org> <82sk5m7oyz.fsf@mid.bfk.de> <87zkztojwh.fsf@willster.local.flamingspork.com> From: Florian Weimer Date: Fri, 21 May 2010 06:43:15 +0000 In-Reply-To: <87zkztojwh.fsf@willster.local.flamingspork.com> (Stewart Smith's message of "Fri\, 21 May 2010 16\:20\:46 +1000") Message-ID: <828w7d69h8.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: Stewart Smith Cc: Christoph Hellwig , xfs@oss.sgi.com * Stewart Smith: > On Thu, 20 May 2010 12:11:00 +0000, Florian Weimer wrote: >> Thanks for confirming my hunch. I don't think it's worth fixing this >> in XFS. The database should call posix_fallocate() before flushing >> its internal cache to the file in essentially random order, but it's >> difficult to get upstream to implement this (the source code is a bit >> hard to follow, unfortunately). > > Which database? Oracle Berkeley DB. > You could always mount with allocsize This happens with "allocsize=3D4194304". > or use other tools to do the preallocation before things got too > bad. Is there a way to transparently preallocate a few GB after the current end of the file? That would be helpful because Berkeley DB wouldn't have to know about it. It's a legacy system, otherwise I would invest more effort into putting some sort of preallocation somewhere deep into Berkeley DB. -- = 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