From owner-freebsd-fs@FreeBSD.ORG Thu Nov 4 14:35:45 2010 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id ACA631065672 for ; Thu, 4 Nov 2010 14:35:45 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from qmta01.westchester.pa.mail.comcast.net (qmta01.westchester.pa.mail.comcast.net [76.96.62.16]) by mx1.freebsd.org (Postfix) with ESMTP id 58DEF8FC08 for ; Thu, 4 Nov 2010 14:35:44 +0000 (UTC) Received: from omta23.westchester.pa.mail.comcast.net ([76.96.62.74]) by qmta01.westchester.pa.mail.comcast.net with comcast id Sywv1f0031c6gX8512bl43; Thu, 04 Nov 2010 14:35:45 +0000 Received: from koitsu.dyndns.org ([98.248.41.155]) by omta23.westchester.pa.mail.comcast.net with comcast id T2bk1f0053LrwQ23j2bksu; Thu, 04 Nov 2010 14:35:45 +0000 Received: by icarus.home.lan (Postfix, from userid 1000) id F3E729B422; Thu, 4 Nov 2010 07:35:42 -0700 (PDT) Date: Thu, 4 Nov 2010 07:35:42 -0700 From: Jeremy Chadwick To: freebsd-fs@FreeBSD.ORG Message-ID: <20101104143542.GA628@icarus.home.lan> References: <20101103030515.GA61758@icarus.home.lan> <201011041429.oA4ETMsV088125@lurza.secnetix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201011041429.oA4ETMsV088125@lurza.secnetix.de> User-Agent: Mutt/1.5.21 (2010-09-15) Cc: Subject: Re: Using an SSD "disk" for / X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Nov 2010 14:35:45 -0000 On Thu, Nov 04, 2010 at 03:29:22PM +0100, Oliver Fromme wrote: > Jeremy Chadwick wrote: > > As for the performance: it's something you'll have to see for yourself. > > The performance is outright amazing when it comes to administrative > > tasks (OS installation, newfs, massive copies of data to/from the SSD, > > updating /usr/src and /usr/ports, etc.). Try a build/install world or > > kernel sometime on an SSD and watch your terminal. You'll be pretty > > impressed. > > What kind of tuning do you apply to those file systems? > > I'm asking because I can't really reproduce those results. > On a machine with plenty of RAM I've created memory disks > for obj and src, which should at least be as fast (probably > even faster) than an SSD. Buildworld was somewhat faster, > compared to standard (well-tuned) UFS+SU filesystems on a > fast SATA HDD, but not _that_ much faster. In fact the > difference was small enough that I stopped using memory > disks and returned to using UFS+SU+noatime (and a few other > tuning options) on a HDD. > > So, if you experience a _dramatic_ speed-up when using SSDs > for buildworld, I would really very much like to know why > this is the case, and what kind of tuning you performed. Literally: absolutely no tuning. I treat the SSD the exact same as I would a standard mechanical HDD: install FreeBSD on it, and that's that. I imagine the performance difference greatly depends on what SSD you're actually using. Again, the Intel drives have the highest IOPS out there (at least in the consumer-grade market), and I can't justify the cost of an SLC-based drive, so I stick to MLC. Possibly you and I have different interpretation of what "dramatic" means? :-) My opinion is that cutting 6-7 full minutes off a buildworld is pretty dramatic. -- | Jeremy Chadwick jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |