From owner-freebsd-questions@FreeBSD.ORG Tue Sep 14 18:32:43 2010 Return-Path: Delivered-To: questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id F2377106566B for ; Tue, 14 Sep 2010 18:32:43 +0000 (UTC) (envelope-from toomas.aas@raad.tartu.ee) Received: from kuller.raad.tartu.ee (kuller.raad.tartu.ee [213.184.43.8]) by mx1.freebsd.org (Postfix) with ESMTP id A1E2D8FC1D for ; Tue, 14 Sep 2010 18:32:43 +0000 (UTC) Received: from kuller.raad.tartu.ee (localhost [127.0.0.1]) by kuller.raad.tartu.ee (Postfix) with ESMTP id EF74739825 for ; Tue, 14 Sep 2010 21:15:17 +0300 (EEST) X-Virus-Scanned: amavisd-new at post.raad.tartu.ee Received: from kuller.raad.tartu.ee ([127.0.0.1]) by kuller.raad.tartu.ee (kuller.raad.tartu.ee [127.0.0.1]) (amavisd-new, port 10024) with LMTP id AZryb7PpRRJ2 for ; Tue, 14 Sep 2010 21:15:17 +0300 (EEST) Received: by kuller.raad.tartu.ee (Postfix, from userid 80) id CC75D39872; Tue, 14 Sep 2010 21:15:16 +0300 (EEST) Received: from 84-50-143-208-dsl.rkv.estpak.ee (84-50-143-208-dsl.rkv.estpak.ee [84.50.143.208]) by webmail.raad.tartu.ee (Horde Framework) with HTTP; Tue, 14 Sep 2010 21:15:16 +0300 Message-ID: <20100914211516.92195onu24td4z4s@webmail.raad.tartu.ee> Date: Tue, 14 Sep 2010 21:15:16 +0300 From: Toomas Aas To: questions@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes"; format="flowed" Content-Disposition: inline Content-Transfer-Encoding: 7bit User-Agent: Internet Messaging Program (IMP) H3 (4.3.7) X-Originating-IP: 84.50.143.208 Cc: Subject: Is it safe to run gjournal on aac-based system (BIO_FLUSH)? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Sep 2010 18:32:44 -0000 Hello! I'm planning to install FreeBSD 8.1 on a system which has Adaptec 4805SAS RAID controller (using aac driver). I'd like to use gjournal for the data partition, but I have some doubts regarding the (lack of) BIO_FLUSH feature. I have another system with FreeBSD 7.3 and a different aac-based controller where I've been using gjournal for 3 years. Every time the system boots, it prints this warning: GEOM_JOURNAL: BIO_FLUSH not supported by aacd1s2. I understand that lack of BIO_FLUSH support means that data cannot be safely flushed to disk and that might cause corruption in case of sudden power loss. Is that correct? Anyway, since this system has battery-backed write cache, I'm not too worried. But on the system where I'm about to install now, the controller doesn't have a battery for its cache. Hence my question - does the aac driver on FreeBSD 8.1 still not support BIO_FLUSH? If so, I should probably avoid using gmirror on this system? -- Toomas Aas