From owner-freebsd-hackers@FreeBSD.ORG Wed Oct 1 09:02:33 2014 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 0513DACA for ; Wed, 1 Oct 2014 09:02:33 +0000 (UTC) Received: from eu1sys200aog124.obsmtp.com (eu1sys200aog124.obsmtp.com [207.126.144.157]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 53A8E17A for ; Wed, 1 Oct 2014 09:02:31 +0000 (UTC) Received: from mail-wi0-f178.google.com ([209.85.212.178]) (using TLSv1) by eu1sys200aob124.postini.com ([207.126.147.11]) with SMTP ID DSNKVCvDH+Ra4b6MoMec82Wsdw7pdHjBNe+5@postini.com; Wed, 01 Oct 2014 09:02:32 UTC Received: by mail-wi0-f178.google.com with SMTP id cc10so1072574wib.5 for ; Wed, 01 Oct 2014 02:02:23 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:message-id:to:subject:cc:reply-to :in-reply-to; bh=aIuwTz+5Yt8whj6pUmpm5BIqAWp1e5WY6UTMvKepGmo=; b=Srgmv72spFjOpbigYHp7RpFA9OMYeQFb+HJPOth0CDAoO+ZkDE5FSIEHP3DqAoEudT dph1S70UdsN/L0lDSQLDtdDM+uGM5VwMwGzBPQpUebKIGtwbuDeImNgb3+vxoFKD4YZR PWg36Y01lr6LINnir+oeONFy6l+FSA4siN5luDQ20xiSId0oKB2oWsyECtn80uKeXrh0 /kE6wyopU55ZUlcOilrywQ+NgT7XoU7YmOSC2ASHTU9mBpKeKes+M9m7vXOx5KGQtPu0 nj/a9LBFcHI22IKiaBYnoQFbi1wqVUPgExs4K8XwshjfHYGaH44h5ZM09x6D/v/G78J7 YgTw== X-Gm-Message-State: ALoCoQnq3sD16mZsuwlH0oPp9+tez8q5B4ZH61MCxwuPbN1Ok8F0e8J20FYmY31KCcxEUSK1UQdEmzTN+rs8MBZK+mStNuT+9qyTt9jUQxlZq86kGJdCUnAt99ipb1bsb0W30TIuQlRetBh9BYpu/ygbEgHjdEOLuQ== X-Received: by 10.180.95.66 with SMTP id di2mr12603972wib.60.1412154143633; Wed, 01 Oct 2014 02:02:23 -0700 (PDT) X-Received: by 10.180.95.66 with SMTP id di2mr12603955wib.60.1412154143533; Wed, 01 Oct 2014 02:02:23 -0700 (PDT) Received: from mech-as221.men.bris.ac.uk (mech-as221.men.bris.ac.uk. [137.222.187.221]) by mx.google.com with ESMTPSA id k2sm422846wjy.34.2014.10.01.02.02.22 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 01 Oct 2014 02:02:22 -0700 (PDT) Received: from mech-as221.men.bris.ac.uk (localhost [127.0.0.1]) by mech-as221.men.bris.ac.uk (8.14.9/8.14.9) with ESMTP id s9192L50084233 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 1 Oct 2014 10:02:21 +0100 (BST) (envelope-from mexas@mech-as221.men.bris.ac.uk) Received: (from mexas@localhost) by mech-as221.men.bris.ac.uk (8.14.9/8.14.9/Submit) id s9192Lhb084232; Wed, 1 Oct 2014 10:02:21 +0100 (BST) (envelope-from mexas) Date: Wed, 1 Oct 2014 10:02:21 +0100 (BST) From: Anton Shterenlikht Message-Id: <201410010902.s9192Lhb084232@mech-as221.men.bris.ac.uk> To: jkh@mail.turbofuzz.com, mexas@bristol.ac.uk Subject: Re: cluster FS? Reply-To: mexas@bristol.ac.uk In-Reply-To: Cc: freebsd-hackers@freebsd.org, allanjude@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 01 Oct 2014 09:02:33 -0000 >From jkh@mail.turbofuzz.com Wed Oct 1 09:26:57 2014 > >You are trying to create an active/active fail-over system with multiple modes. You cannot get there from where you are starting. This is basically a “start over” proposition, and why folks like NetApp and EMC sell a lot of fileservers to replace existing SAN solutions. So are you saying that the SAN model is not good for active/active failover with multiple nodes? Clearly if SAN itself fails, then the data is not accessible. From what I understand, in really mission critical systems people use multiple SANs with multiple nodes, with some extra data synchronisation mechanisms between those multiple SANs. Are you saying there are better solutions for high availability? Thanks Anton