From owner-freebsd-stable@FreeBSD.ORG Wed Sep 6 14:08:47 2006 Return-Path: X-Original-To: stable@freebsd.org Delivered-To: freebsd-stable@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id AB70B16A4DD for ; Wed, 6 Sep 2006 14:08:47 +0000 (UTC) (envelope-from Philippe.Pegon@crc.u-strasbg.fr) Received: from mailhost.u-strasbg.fr (mailhost.u-strasbg.fr [130.79.200.157]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0EE4343D45 for ; Wed, 6 Sep 2006 14:08:46 +0000 (GMT) (envelope-from Philippe.Pegon@crc.u-strasbg.fr) Received: from [IPv6:2001:660:2402:1001:20e:cff:fe60:e734] (apophis.u-strasbg.fr [IPv6:2001:660:2402:1001:20e:cff:fe60:e734]) by mailhost.u-strasbg.fr (8.13.6/jtpda-5.5pre1) with ESMTP id k86E8hsV066547 ; Wed, 6 Sep 2006 16:08:43 +0200 (CEST) Message-ID: <44FED689.8070202@crc.u-strasbg.fr> Date: Wed, 06 Sep 2006 16:09:13 +0200 From: Philippe Pegon User-Agent: Thunderbird 1.5.0.4 (X11/20060611) MIME-Version: 1.0 To: =?ISO-8859-1?Q?Ulrich_Sp=F6rlein?= References: <239947161@misc1.1822direkt.com> In-Reply-To: <239947161@misc1.1822direkt.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.0.2 (mailhost.u-strasbg.fr [IPv6:2001:660:2402::157]); Wed, 06 Sep 2006 16:08:44 +0200 (CEST) X-Virus-Scanned: ClamAV 0.88.4/1814/Wed Sep 6 15:12:35 2006 on mr7.u-strasbg.fr X-Virus-Status: Clean X-Spam-Status: No, score=0.0 required=5.0 tests=AWL,NO_RELAYS autolearn=disabled version=3.1.4 X-Spam-Checker-Version: SpamAssassin 3.1.4 (2006-07-25) on mr7.u-strasbg.fr Cc: stable@freebsd.org Subject: Re: Snapshot duration, performance and how to avoid I/O lock X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Sep 2006 14:08:47 -0000 Ulrich Spörlein wrote: > Hi, Hi, > I have to create regular snapshots of several volumes roughly 1.4TB in > size (each). But using mksnap_ffs takes a lot of time (45 minutes) and > it looks like it could be speed up. [snip] > Another thing is blocking other disk I/O while snapshotting. Right now I did > a ls(1) in the .snap directory, so I understand the filesystem is now suspended. > The workaround would then be to "dont do that". But what if other snapshots are > accessed during that time? I want to provide yesterdays snapshot to our users > while taking the current snapshot and providing access to the newest data at the > same time. I had seen that a long time ago (on another controller), and it seems it's not better today, our post from june 2005 without response at the end : http://docs.freebsd.org/cgi/getmsg.cgi?fetch=410600+0+archive/2005/freebsd-stable/20050612.freebsd-stable http://docs.freebsd.org/cgi/getmsg.cgi?fetch=463968+0+archive/2005/freebsd-stable/20050612.freebsd-stable -- Philippe Pegon