Return-Path: Received: from mxout12.cac.washington.edu ([140.142.33.31]:52896 "EHLO mxout12.cac.washington.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932130Ab0HJSUG convert rfc822-to-8bit (ORCPT ); Tue, 10 Aug 2010 14:20:06 -0400 Received: from smtp.washington.edu (smtp.washington.edu [140.142.32.205] (may be forged)) by mxout12.cac.washington.edu (8.14.3+UW09.11/8.14.3+UW09.11) with ESMTP id o7AIJeej020344 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 10 Aug 2010 11:19:40 -0700 Content-Type: text/plain; charset=us-ascii Subject: Re: Tuning NFS client write pagecache From: David Brodbeck In-Reply-To: Date: Tue, 10 Aug 2010 11:19:39 -0700 Message-Id: <2CCA2E8E-8606-48A1-91D2-3E91253E3004@u.washington.edu> References: <4C5BFE47.8020905@mxtelecom.com> <20100806132620.GA2921@merit.edu> <1281116260.2900.6.camel@heimdal.trondhjem.org> <1281123565.2900.17.camel@heimdal.trondhjem.org> <98DC3FB9-72A7-44CF-AB8B-914F2379B01B@oracle.com> To: linux-nfs@vger.kernel.org Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Aug 10, 2010, at 10:52 AM, Peter Chacko wrote: > And caching itself is not useful for any streaming datapath.(Be it > NFS cache,or memory cache or cpu cache or even a web cache).. backup > is write-only operation, for all file objects... It seems to me this is only true if you're talking strictly about full backups. Any kind of incremental or differential backup is likely to do a significant amount of reading in order to determine what files need to be sent, unless it's storing data about each backup locally. rsync, for example, needs to read from both filesystems to build up its file list. -- David Brodbeck System Administrator, Linguistics University of Washington