From owner-freebsd-hackers@FreeBSD.ORG Wed Sep 3 11:23:03 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9A6C116A4BF; Wed, 3 Sep 2003 11:23:03 -0700 (PDT) Received: from silver.he.iki.fi (helenius.fi [193.64.42.241]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2999E43FD7; Wed, 3 Sep 2003 11:23:02 -0700 (PDT) (envelope-from pete@he.iki.fi) Received: from he.iki.fi (h81.vuokselantie10.fi [193.64.42.129]) by silver.he.iki.fi (8.12.9/8.11.4) with ESMTP id h83IN02k012985; Wed, 3 Sep 2003 21:23:00 +0300 (EEST) (envelope-from pete@he.iki.fi) Message-ID: <3F563183.3080103@he.iki.fi> Date: Wed, 03 Sep 2003 21:22:59 +0300 From: Petri Helenius User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Max Clark References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit cc: freebsd-hackers@freebsd.org cc: freebsd-performance@freebsd.org Subject: Re: 20TB Storage System (fsck????) X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 03 Sep 2003 18:23:03 -0000 Max Clark wrote: >Ohh, that's an interesting snag. I was under the impression that 5.x w/ PAE >could address more than 4GB of Ram. > > It does. However as long as a pointer is 32 bits, your address space for a process is maxed out at 4G which translates to about 2.5G user after kernel and other things have taken their toll. >If fsck requires 700K for each 1GB of Disk, we are talking about 7GB of Ram >for 10TB of disk. Is this correct? Will PAE not function correctly to give >me 8GB of Ram? To check 10TB of disk? > PAE functions correctly but does not provide for 7G address space. >Is there anyway to bypass this requirement and split fsck into smaller >chunks? Being able to fsck my disk is kinda important. > > Yes, you do that by splitting up the filesystem to smaller filesystems. Kind of obvious? >I have zero experience with either itanium or opteron. What is the current >status of support for these processors in FreeBSD? What would the preferred >CPU be? Will there be PCI cards that I would not be able to use in either of >these systems? > > I´m personally biased towards the Opteron, but that´s more based on that it makes more sense than their technical merits so far (because neither has too much). Both CPU´s should work fine with 5.2 according to the TODO list. Meanwhile I suggest you play with the number of inodes on the 10TB filesystem and see how that affects the memory usage. Pete