From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: Versioning file system Date: Wed, 20 Jun 2007 10:10:40 -0700 Message-ID: <46795F90.5030602@zytor.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Trond Myklebust , akpm@linux-foundation.org, alan , Chris Snook , Jack Stone , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Lennart Sorensen , viro@zeniv.linux.org.uk To: Bryan Henderson Return-path: Received: from terminus.zytor.com ([192.83.249.54]:48185 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755848AbXFTRPT (ORCPT ); Wed, 20 Jun 2007 13:15:19 -0400 In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Bryan Henderson wrote: >> The directory is quite visible with a standard 'ls -a'. Instead, >> they simply mark it as a separate volume/filesystem: i.e. the fsid >> differs when you call stat(). The whole thing ends up acting rather like >> our bind mounts. > > Hmm. So it breaks user space quite a bit. By break, I mean uses that > work with more conventional filesystems stop working if you switch to > NetAp. Most programs that operate on directory trees willingly cross > filesystems, right? Even ones that give you an option, such as GNU cp, > don't by default. > > But if the implementation is, as described, wildly successful, that means > users are willing to tolerate this level of breakage, so it could be used > for versioning too. > > But I think I'd rather see a truly hidden directory for this (visible only > when looked up explicitly). > When I administered a bunch of netapps I remember turning the visible .snapshots off. -hpa