From owner-freebsd-hackers@FreeBSD.ORG Thu Oct 9 22:35:16 2008 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 90443106568A for ; Thu, 9 Oct 2008 22:35:16 +0000 (UTC) (envelope-from zbeeble@gmail.com) Received: from wx-out-0506.google.com (wx-out-0506.google.com [66.249.82.233]) by mx1.freebsd.org (Postfix) with ESMTP id 286CA8FC08 for ; Thu, 9 Oct 2008 22:35:15 +0000 (UTC) (envelope-from zbeeble@gmail.com) Received: by wx-out-0506.google.com with SMTP id s17so106401wxc.7 for ; Thu, 09 Oct 2008 15:35:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type:references; bh=dRfH6EVdAuShGa+AWz183PSfQqmN+INHbDvVUIPieq4=; b=oCJKKA8eEZIYaE5SL67Bef/ubEs7y8qoUA0qk9yHghQ3HPau0FXdicvHzzTLvrG9jE WqeOBBMTtcn3/5VTkHYb3tGcNZ/QRM/s0OMHG0eWIJp+k+MZ9WIuMAMcdLu9xgH998A+ JEERmSw3xKgtCikf8jUfRHU9Wuu8kdOWGEt/o= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:references; b=RYfcJHh+NjPDkZ9cNFtDlqr0sypgcyMIaPoVgPphWepAhO3Iv+qwNucBFW+vzVtNcJ OzfzNvbvnU2TgrKcMn+OsCAvjH1r2AxcZqOdPWNoWbfVrEu9J+9bZEnQ/8jupt1QSa4a bqPT1J17t5SZTqPB714+9mizNmIorz8X8vfaU= Received: by 10.150.203.8 with SMTP id a8mr700604ybg.146.1223582411840; Thu, 09 Oct 2008 13:00:11 -0700 (PDT) Received: by 10.150.137.11 with HTTP; Thu, 9 Oct 2008 13:00:11 -0700 (PDT) Message-ID: <5f67a8c40810091300v37f089a8pa8828f7fba5e9c@mail.gmail.com> Date: Thu, 9 Oct 2008 16:00:11 -0400 From: "Zaphod Beeblebrox" To: "Matthew Dillon" In-Reply-To: <200810091940.m99Jed1t041572@apollo.backplane.com> MIME-Version: 1.0 References: <200810091421.m99ELEcm007901@lurza.secnetix.de> <200810091940.m99Jed1t041572@apollo.backplane.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-hackers@freebsd.org Subject: Re: continuous backup solution for FreeBSD X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 09 Oct 2008 22:35:16 -0000 On Thu, Oct 9, 2008 at 3:40 PM, Matthew Dillon wrote: > (ZFS has a way to do something similar but I do not know what the > various advantages or disadvantages of using the feature are). The only current way to do this on ZFS is to snapshot (very cheap) and stream the differences between the current snapshot and the previous snapshot to the remote host. The remote host can store the flat files or store the filesystem (that is: the streams can feed into new snapshots of the filesystem on the remote machine). Like Hammer, this gives history on both the local machine and the remote machine and is amazingly efficient. Unlike hammer, the process is not automated by the filesystem. You need a script that does "zfs snaphot..." followed by "zfs send ... | ssh zfs receive ..." --- such that each individual backup is a job rather than the connection approach you discribe for Hammer. Unlike Hammer, ZFS doesn't, by default, keep all history. I was speculating earlier that this might be possible to make as a ZFS module, though.