From owner-freebsd-current@FreeBSD.ORG Wed Jun 10 16:11:25 2009 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 09C95106567B; Wed, 10 Jun 2009 16:11:25 +0000 (UTC) (envelope-from cdillon@wolves.k12.mo.us) Received: from mail.wolves.k12.mo.us (mail.wolves.k12.mo.us [207.160.214.1]) by mx1.freebsd.org (Postfix) with ESMTP id CC6768FC26; Wed, 10 Jun 2009 16:11:24 +0000 (UTC) (envelope-from cdillon@wolves.k12.mo.us) Received: from localhost (localhost [127.0.0.1]) by mail.wolves.k12.mo.us (Postfix) with ESMTP id 32B3EB87A; Wed, 10 Jun 2009 10:55:16 -0500 (CDT) X-Virus-Scanned: amavisd-new at wolves.k12.mo.us Received: from mail.wolves.k12.mo.us ([127.0.0.1]) by localhost (mail.wolves.k12.mo.us [127.0.0.1]) (amavisd-new, port 10024) with LMTP id luGhZKllryz2; Wed, 10 Jun 2009 10:55:16 -0500 (CDT) Received: from wolves.k12.mo.us (mail.wolves.k12.mo.us [207.160.214.1]) by mail.wolves.k12.mo.us (Postfix) with ESMTP id 07876B809; Wed, 10 Jun 2009 10:55:15 -0500 (CDT) Received: from rstech28.int.wolves.k12.mo.us (rstech28.int.wolves.k12.mo.us [10.1.3.200]) by www.wolves.k12.mo.us (Horde Framework) with HTTP; Wed, 10 Jun 2009 10:55:15 -0500 Message-ID: <20090610105515.138862z6opgohgtf@www.wolves.k12.mo.us> Date: Wed, 10 Jun 2009 10:55:15 -0500 From: Chris Dillon To: Dmitry Morozovsky References: <20090609172142.GA92146@ebi.local> <20090609.195750.41709103.sthaug@nethelp.no> <86hbyowgj6.fsf@ds4.des.no> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes"; format="flowed" Content-Disposition: inline Content-Transfer-Encoding: 7bit User-Agent: Internet Messaging Program (IMP) 4.3.3 / FreeBSD-6.4 Cc: freebsd-hackers@freebsd.org, freebsd-current@freebsd.org Subject: Re: sysinstall, GJOURNAL and ZFS X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Jun 2009 16:11:26 -0000 Quoting Dmitry Morozovsky : > Well, I can see at least one rather big problem with bgfsck (or with > snapshots to be more precise): inappropriate time of file system > lock on snapshot creation. On not-too-big 300G ufs2 not-too-heavy > loaded snapshot creation time is 20+ minutes, and 5+ from that file > system blocked even on reads. This looks unacceptable for me for > any real use. The snapshot time depends heavily on the I/O throughput of your disk subsystem. On a several year old system with 5 x 72GB 15KRPM U320 SCSI drives in a RAID5 array, a fairly well loaded 260GB filesystem (90GB used, 354K out of 8M inodes used, and several hundred MB to a GB of changes per day) completes a snapshot in exactly 2 minutes. 2 minutes is still too long to be blocking I/O in the middle of the day when it is being actively used, so I just take 1 snapshot per day while it is idle. I would love to put ZFS on this system so that I could have finer grained snapshots, but I need user quota support which our ZFS currently lacks. -- Chris Dillon - NetEng/SysAdm Reeds Spring R-IV School District Technology Department 175 Elementary Rd. Reeds Spring, MO 65737 Voice: 417-272-8266 Fax: 417-272-0015