From owner-freebsd-stable@FreeBSD.ORG Wed Feb 20 16:37:34 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8713F16A400 for ; Wed, 20 Feb 2008 16:37:34 +0000 (UTC) (envelope-from kkutzko@teksavvy.com) Received: from ironport2-out.pppoe.ca (ironport2-out.pppoe.ca [206.248.154.182]) by mx1.freebsd.org (Postfix) with ESMTP id 2F1D213C45A for ; Wed, 20 Feb 2008 16:37:33 +0000 (UTC) (envelope-from kkutzko@teksavvy.com) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Ao8CAHPmu0dMCqa7/2dsb2JhbACKc6V3BA X-IronPort-AV: E=Sophos;i="4.25,381,1199682000"; d="scan'208";a="14753692" Received: from mail.pppoe.ca ([65.39.192.132]) by ironport2-out.pppoe.ca with ESMTP; 20 Feb 2008 11:37:30 -0500 Received: from kevin ([76.10.166.187]) by mail.pppoe.ca (Internet Mail Server v1.0) with ASMTP id ASF60230; Wed, 20 Feb 2008 11:37:30 -0500 From: "Kevin K" To: "'Ivan Voras'" , References: <20080220035752.GR99258@elvis.mu.org> <4594886.5961203490569242.JavaMail.root@ly.sdf.com> In-Reply-To: Date: Wed, 20 Feb 2008 11:37:28 -0500 Message-ID: <001d01c873de$e1cef5b0$a56ce110$@com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: Achz3lsyvJK8x8YrRpSiatAhfRYETgAABJoA Content-Language: en-us Cc: Subject: RE: Dual Core Xeon / i386 install w/ more than 4gb of RAM 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, 20 Feb 2008 16:37:34 -0000 Thank you all for your suggestions. I have been trying to push to move = to amd64 architecture for all the reasons you all stated. For the = record, we tested PAE on one machine, booted the kernel w/ nextboot and = it crashed about 15 minutes later. I will consider configuring a dump = device to analyze the kernel dumps, but for now we reverted to the = original i386 kernel and are likely going to scrap the PAE idea and move = to amd64. This was a management decision (obviously) and the people who originally = built this box (long before I was there), did not have enough experience = or foresight. i was hoping for alternative suggestions to reduce = downtime of these boxes, such as recompiling amd64 manually instead of a = fresh install. These boxes are just Apache, Mysql, PHP type boxes. Nothing exotic or = fancy. Thanks again for your suggestions. I am trying my best to relay the = reasoning and rock-solid logic ;) -----Original Message----- From: owner-freebsd-stable@freebsd.org = [mailto:owner-freebsd-stable@freebsd.org] On Behalf Of Ivan Voras Sent: Wednesday, February 20, 2008 11:35 AM To: freebsd-stable@freebsd.org Subject: Re: Dual Core Xeon / i386 install w/ more than 4gb of RAM Tom Samplonius wrote: > Is PAE really that stable? I thought it was fairly unpolished, = mainly because PAE is seen as a weak kludge implemented by Intel because = they all thought we would all be using Itanium's by now. Intel reversed = their folly pretty quickly, adopted the x86-64 extensions as-is from = AMD, and pushed them onto every piece of silicon they make. Architecturally, it's a nasty kludge. As far as stability on FreeBSD is = concerned, my only machine under PAE with 4 GB RAM (without PAE it would = use a bit over 3 GB) is very solid on 6-STABLE. > I also really don't know how anyone would properly use 16GB of RAM = under PAE anyways? Each process is going to limited to just under 4GB. = The kernel memory space can't be bigger than 4GB either, so forget about = a huge disk cache. As I understand it, one possible benefit could be to use the memory for = disk / file cache. AFAIK the pages are just pages, without distinction = where they are mapped, and for example, if you run PostgreSQL, it = couldn't use more than 4 GB for its own data (actually closer to 2 GB = because of some sysvshm issues) but it will indirectly use the cache. > And is there some really stability fear about FreeBSD on x86-64? = Seems just the same as i386. I agree, FreeBSD on amd64 is very stable.