From owner-freebsd-stable@FreeBSD.ORG Fri May 25 10:01:14 2012 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 789D61065675 for ; Fri, 25 May 2012 10:01:14 +0000 (UTC) (envelope-from petefrench@ingresso.co.uk) Received: from constantine.ingresso.co.uk (constantine.ingresso.co.uk [IPv6:2a02:b90:3002:e550::3]) by mx1.freebsd.org (Postfix) with ESMTP id 142688FC0A for ; Fri, 25 May 2012 10:01:14 +0000 (UTC) Received: from dilbert.london-internal.ingresso.co.uk ([10.64.50.6] helo=dilbert.ingresso.co.uk) by constantine.ingresso.co.uk with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76 (FreeBSD)) (envelope-from ) id 1SXrKK-000Fmj-5l; Fri, 25 May 2012 11:00:56 +0100 Received: from petefrench by dilbert.ingresso.co.uk with local (Exim 4.77 (FreeBSD)) (envelope-from ) id 1SXrKK-000M5Y-53; Fri, 25 May 2012 11:00:56 +0100 To: janm@transactionware.com, petefrench@ingresso.co.uk In-Reply-To: Message-Id: From: Pete French Date: Fri, 25 May 2012 11:00:56 +0100 Cc: freebsd-stable@freebsd.org Subject: Re: VirtualBox, AIO and zvol's - a cautionary tale 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: Fri, 25 May 2012 10:01:14 -0000 > I have seen similar behaviour, but I did not disable AIO to solve it. Instead, in the VirtualBox VM, I made sure that the storage controller was created with the "--hostiocache on" option. Without that, the virtual machines were unreliable on ZFS with the same behaviour you saw. Interesting. I have this setting "Off" - but my machines were perfectly reliable until AIO was added to the mix. Are yours directly on top of a zvol as the underlying disc, or using files on ZFS ? Will try enabling that setting - thoigh as it is stable anyway it wont make a lot of diffeernce I hope! cheers, -pete.