From mboxrd@z Thu Jan 1 00:00:00 1970 From: "J. R. Okajima" Subject: Re: [LSF/MM ATTEND] Stackable Union Filesystem Implementation Date: Wed, 08 Jan 2014 14:10:09 +0900 Message-ID: <6469.1389157809@jrobl> References: <20140107122301.GC16640@quack.suse.cz> Cc: Jan Kara , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, lsf-pc@lists.linux-foundation.org To: Saket Sinha Return-path: Received: from mail03-md.ns.itscom.net ([175.177.155.113]:45907 "EHLO mail03-md.ns.itscom.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750898AbaAHFKN (ORCPT ); Wed, 8 Jan 2014 00:10:13 -0500 In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Saket Sinha: > Several implementations of union file system fusion were evaluated. > The results of the evaluation is shown at the below link- > http://www.4shared.com/download/7IgHqn4tce/1_online.png As far as I know, aufs supports NFS branches and also you can export aufs via NFS. For example, http://sourceforge.net/p/aufs/mailman/message/20639513/ > 2. if only the file metadata are modified, then do not > copy the whole file on the read-write files system but > only the metadata (stored with a file named as the file > itself prefixed by '.me.') Once I have considered such approach to implement it in aufs. But I don't think it a good idea to store metadata in multiple places, one in the original file and the other is in .me. file. For such purpose, a "block device level union" (instead of filesystem level union) may be an option for you, such as "dm snapshot". J. R. Okajima