From mboxrd@z Thu Jan 1 00:00:00 1970 From: Valerie Aurora Henson Subject: Re: Data-deduplication? Date: Thu, 16 Oct 2008 15:25:01 -0400 Message-ID: <20081016192501.GE16946@shell> References: <20081012020629.GA14615@bludgeon.org> <1223895734.7032.1.camel@think.oraclecorp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ray Van Dolson , linux-btrfs@vger.kernel.org To: Chris Mason Return-path: In-Reply-To: <1223895734.7032.1.camel@think.oraclecorp.com> List-ID: On Mon, Oct 13, 2008 at 07:02:14AM -0400, Chris Mason wrote: > On Sat, 2008-10-11 at 19:06 -0700, Ray Van Dolson wrote: > > I recall their being a thread here a number of months back regarding > > data-deduplication support for bttfs. > > > > Did anyone end up picking that up and giving a go at it? Block level > > data dedup would be *awesome* in a Linux filesystem. It does wonders > > for storing virtual machines w/ NetApp and WAFL, and even ZFS doesn't > > have this feature yet (although I've read discussions on them looking > > to add it). > > > > So far nobody has grabbed this one, but I've had more requests (no > shocker there, the kvm people are interested in it too). It probably > won't make 1.0 but the disk format will be able to support it. Both deduplication and compression have an interesting side effect in which a write to a previously "allocated" block can return ENOSPC. This is even more exciting when you factor in mmap. Any thoughts on how to handle this? -VAL