From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lexington Luthor Subject: Re: COW files Date: Sat, 29 Oct 2005 14:49:55 +0100 Message-ID: References: <43636C13.5040307@slaphack.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: <43636C13.5040307@slaphack.com> Sender: news List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: reiserfs-list@namesys.com David Masover wrote: > Gregory Maxwell wrote: > >> Files could be COWed by a flag on the cp command (or really, perhaps >> that should be the default behavior) or with a utility (perhaps run as >> a periodic script to locate duplicates and COW them. This would >> greatly speed up the process of copying files. > > Should be on the cp command, but you have to change the cp source for > that, and everything implementing "copy", including desktop managers. > There's currently no "copy" system call. So it's more than just a plugin. > I would love something like this for entire directory trees. Perhaps with a reiser4 specific tool that does a COW cp -al. At the moment, I have to cp -al and use a userspace solution (LD_PRELOADed library which traps the open call) to get working COW on reiser4. I am not concerned too much with space usage, but speed is very important. This is usually not a problem with reiser4 because it so rarely hits the disk with COW trees. - LL