From owner-freebsd-questions@FreeBSD.ORG Sat Jul 19 20:03:33 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 45850F69 for ; Sat, 19 Jul 2014 20:03:33 +0000 (UTC) Received: from mail.magehandbook.com (173-8-4-45-WashingtonDC.hfc.comcastbusiness.net [173.8.4.45]) by mx1.freebsd.org (Postfix) with ESMTP id 18AD229DB for ; Sat, 19 Jul 2014 20:03:32 +0000 (UTC) Received: from [192.168.1.50] (Mac-Pro.magehandbook.com [192.168.1.50]) by mail.magehandbook.com (Postfix) with ESMTP id 3hG0Nd68N4z173 for ; Sat, 19 Jul 2014 15:57:37 -0400 (EDT) Date: Sat, 19 Jul 2014 15:57:37 -0400 From: Daniel Staal To: freebsd-questions@freebsd.org Subject: Re: deciding UFS vs ZFS Message-ID: <578E7D82A34085A024A9BD33@[192.168.1.50]> In-Reply-To: <20140718180416.715cdc0b@gumby.homeunix.com> References: <20140713190308.GA9678@bewilderbeast.blackhelicopters.org> <20140714071443.42f615c5@X220.alogt.com> <53C326EE.1030405@my.hennepintech.edu> <20140714111221.5d4aaea9@X220.alogt.com> <20140715143821.23638db5@gumby.homeunix.com> <20140716143929.74209529@gumby.homeunix.com> <20140718180416.715cdc0b@gumby.homeunix.com> X-Mailer: Mulberry/4.0.8 (Mac OS X) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 19 Jul 2014 20:03:33 -0000 --As of July 18, 2014 6:04:16 PM +0100, RW is alleged to have said: >> "I was really more interested in whether ZFS (with ARC) is faster than >> UFS with FreeBSD's own file caching. A lot of people say that putting >> an OS on SSD gives a significant speed-up. 16GB should be more than >> enough to keep the important system files in memory, so it sounds like >> smarter caching might be useful." >> >> If you want speed sure UFS is faster on the same machine, but that's >> because its doing less. > > Yes, I know ZFS has overheads, but ARC is potentially better than OS > caching. The question was whether, with a decent amount memory, ZFS can > actually be faster than UFS. --As for the rest, it is mine. Checking would take extensive work, and I think it would be *heavily* workload/hardware/tuning dependent, but I suspect there are probably cases where it would be. For a similar type of example: Turning on compression in ZFS can improve speed, depending on the data and the hardware. If it takes less time to compress/uncompress data than it does to write the difference to disk it speeds up; so with highly compressible data and light compression you often get higher speeds. There are several of that types of trade-offs available in ZFS, and you can tune for different uses. I don't think anyone has done comparisons, but it's probably possible that ZFS is faster under certain circumstances, even with a one-disk pool. Daniel T. Staal --------------------------------------------------------------- This email copyright the author. Unless otherwise noted, you are expressly allowed to retransmit, quote, or otherwise use the contents for non-commercial purposes. This copyright will expire 5 years after the author's death, or in 30 years, whichever is longer, unless such a period is in excess of local copyright law. ---------------------------------------------------------------