From owner-freebsd-fs@FreeBSD.ORG Tue Jul 8 23:14:45 2008 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 13F841065673 for ; Tue, 8 Jul 2008 23:14:45 +0000 (UTC) (envelope-from kris@FreeBSD.org) Received: from weak.local (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 4ADC78FC12; Tue, 8 Jul 2008 23:14:44 +0000 (UTC) (envelope-from kris@FreeBSD.org) Message-ID: <4873F4E9.3040203@FreeBSD.org> Date: Wed, 09 Jul 2008 01:14:49 +0200 From: Kris Kennaway User-Agent: Thunderbird 2.0.0.14 (Macintosh/20080421) MIME-Version: 1.0 To: CZUCZY Gergely References: <20080708100701.57031cda@twoflower.in.publishing.hu> <4873C4FA.2020004@FreeBSD.org> <20080708221327.5c1d0e92@mort.in.publishing.hu> <4873CF6C.7000205@FreeBSD.org> <20080708225449.1070252d@mort.in.publishing.hu> In-Reply-To: <20080708225449.1070252d@mort.in.publishing.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-fs@freebsd.org Subject: Re: Thinking of using ZFS/FBSD for a backup system X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Jul 2008 23:14:45 -0000 CZUCZY Gergely wrote: > On Tue, 08 Jul 2008 22:34:52 +0200 > Kris Kennaway wrote: >>> I've finetuned ZFS as much as I could, I've read every little tiny >>> bit of hint/information/whatever that was available and I couldn't >>> get rid of those kmem_size panics in -RELEASE and -STABLE. >> Well, it's still almost certainly because you aren't setting >> kmem_size high enough. As you saw, that is the only thing I tuned >> (disabling prefetch is just for performance in my environment). >> >> If you can't set it high enough because you don't have enough RAM, >> that means your system does't have enough RAM to run ZFS, not that >> ZFS is unstable. > I've had a box with 2GB of memory for it, and around 5-6 filesystems. > I've set kmem_size as large as it was allowed, not a bit smaller. > > Where's the guide showing how much memory should I have for a setup? > How can "enough memory" be determined for a setup, without having > panics? I don't know; empirically my setup is an upper bound. How large was "as large as it was allowed" for you? Kris