From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q16HeDd8152855 for ; Mon, 6 Feb 2012 11:40:13 -0600 Message-ID: <4F301079.9010505@sgi.com> Date: Mon, 06 Feb 2012 11:40:09 -0600 From: Bill Kendall MIME-Version: 1.0 Subject: Re: [PATCH] xfsdump: use the full 32-bit generation number References: <1325880565-20934-1-git-send-email-wkendall@sgi.com> <20120205133648.GA27225@infradead.org> In-Reply-To: <20120205133648.GA27225@infradead.org> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Christoph Hellwig Cc: xfs@oss.sgi.com Christoph Hellwig wrote: > On Fri, Jan 06, 2012 at 02:09:25PM -0600, Bill Kendall wrote: >> dump format version has been bumped to 3. xfsdump also required changes to >> its inode-to-generation cache. This map is not persistent though, so no >> compatibility or version changes were required there. > > Shouldn't the be an option to still generate the old format for > compatibility reasons? The new format contains more information than the old. The new xfsrestore can drop back to using 12-bit generation numbers even if the dump used 32 bits. It will do this automatically when applying a series of restores if the oldest dump used only 12 bits. It's possible that a site would revert to an old xfsdump in the middle of a series of incremental backups, allowing for the oldest backup to use 32-bit generation numbers and a newer backup to use only 12 bits. xfsrestore won't get this right, so a case could be made for having a "force 12-bit generation numbers" option on xfsrestore. You were referring to an xfsdump option. What use case did you have in mind? Compatibility with an old restore? Thanks, Bill _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs