From owner-freebsd-stable@FreeBSD.ORG Mon Apr 5 20:37:30 2010 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 536EC1065678 for ; Mon, 5 Apr 2010 20:37:30 +0000 (UTC) (envelope-from tonix@interazioni.it) Received: from mx02.interazioni.net (mx02.interazioni.net [80.94.114.204]) by mx1.freebsd.org (Postfix) with ESMTP id B22088FC27 for ; Mon, 5 Apr 2010 20:37:29 +0000 (UTC) Received: (qmail 55635 invoked by uid 88); 5 Apr 2010 20:37:28 -0000 Received: from unknown (HELO ?192.168.0.102?) (tonix@interazioni.it@94.164.190.76) by relay.interazioni.net with ESMTPA; 5 Apr 2010 20:37:27 -0000 Message-ID: <4BBA4A04.80005@interazioni.it> Date: Mon, 05 Apr 2010 22:37:24 +0200 From: "Tonix (Antonio Nati)" User-Agent: Thunderbird 2.0.0.24 (Windows/20100228) MIME-Version: 1.0 To: Maciej Jan Broniarz References: <1209800810.33861270466947931.JavaMail.root@dagobah.intersec.pl> <4BBA05A2.40706@intertainservices.com> <4BBA1823.1090305@gausus.net> <4BBA4334.1020506@interazioni.it> <4BBA4478.7030302@gausus.net> In-Reply-To: <4BBA4478.7030302@gausus.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-stable@freebsd.org Subject: Re: fault tolerant web servers on freebsd 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: Mon, 05 Apr 2010 20:37:30 -0000 Maciej Jan Broniarz ha scritto: > W dniu 10-04-05 22:08, Tonix (Antonio Nati) pisze: >> Maciej Jan Broniarz ha scritto: >>> W dniu 10-04-05 17:45, Mike Jakubik pisze: > > >> Just to use exact words, fault toulerancy is not possible with any >> FreeBSD/Linux O.S. >> F.T. means outage can occur in every moment, but all current operation >> will be always completed by other equipments; so there will not be >> interrupted/lost operations. > > Hmm. Thanks for the tip. Which *NIX os can be used to build an FT > solution then? Solaris? AIX? HP-UX? For a FT solution you need usually an hardware solution, very expensive. Server must have all doubled, with custom chips for checking if parts are working (and which part is broken, which may not be easy to understand). VMware claims to have a software fault toulerant solution, syncronizing two servers in real-time, but I don't know the efficiency. The most ISP use HA solutions, which are ok for the most of WEB/e-mail operations. Operations are not available for a few milliseconds/seconds, depending on the architecture you use. Just to complete, drbd+heartbeat are NOT FT. They are HA. When the master server goes down, backup server must acknowledge the new status, then mount the replicated disk (think to disk check!), then start services working on that disk. So this solution needs a lot of seconds, probably minutes to work. With a good carp architecture, you just need milliseconds. Tonino -- ------------------------------------------------------------ Inter@zioni Interazioni di Antonio Nati http://www.interazioni.it tonix@interazioni.it ------------------------------------------------------------