From owner-freebsd-hackers@FreeBSD.ORG Sat Jan 23 02:40:04 2010 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E4CEE106568B for ; Sat, 23 Jan 2010 02:40:03 +0000 (UTC) (envelope-from jhellenthal@gmail.com) Received: from qw-out-2122.google.com (qw-out-2122.google.com [74.125.92.24]) by mx1.freebsd.org (Postfix) with ESMTP id 8D6E98FC08 for ; Sat, 23 Jan 2010 02:40:03 +0000 (UTC) Received: by qw-out-2122.google.com with SMTP id 5so443253qwd.7 for ; Fri, 22 Jan 2010 18:40:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:date:from:to:cc :subject:in-reply-to:message-id:references:user-agent :x-openpgp-key-id:x-openpgp-key-fingerprint:mime-version :content-type; bh=Vi4QMMMItXrdmvUridc26XW47EJh1Ae4LrUa2EuZmR4=; b=XEIsokSZawMgiKxOUct3mWNSXEN39lQniMfBa8dmW6GLNuOz7Cr/r7nvJvU6brnczp cjiLX6rSmU0fHHFB9g1Uv0xZby6wCy1JJ0JA6B5g0zKC79R3/Rr4lUdpSmatcX4lywdC fMv1IZHSr1kePZaZAYqNYrZzb4UfcXQ9mOeOQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:x-openpgp-key-id:x-openpgp-key-fingerprint:mime-version :content-type; b=Zve14o8hZ4kz+7qXF1704Rj+sWOf2LhL9qqvHTtTJs0EGsSKS0XcPQF73nwF1kKGml k5e3qd91YpEenpf/+unlZvrpuMuC9qCk3a2I3AbsYA94mNWONIUz4r7zX4PldD+OdjY7 F4mD5uuqyOCD46nocKSOWgRafss94jiEFxlaw= Received: by 10.224.121.203 with SMTP id i11mr2513796qar.199.1264214402740; Fri, 22 Jan 2010 18:40:02 -0800 (PST) Received: from centel.dataix.local (ppp-22.219.dialinfree.com [209.172.22.219]) by mx.google.com with ESMTPS id 22sm2160844qyk.2.2010.01.22.18.39.58 (version=TLSv1/SSLv3 cipher=RC4-MD5); Fri, 22 Jan 2010 18:40:01 -0800 (PST) Sender: "J. Hellenthal" Date: Fri, 22 Jan 2010 21:39:48 -0500 From: jhell To: Artem Belevich In-Reply-To: Message-ID: References: <7f14551c1001190119x46c6b04dx2362cd1252f0d81@mail.gmail.com> <7f14551c1001190216w49814186n1ada2b721380502b@mail.gmail.com> <4B55C5A6.2020109@DataIX.net> <20100120111433.25801pnmhrxnirok@webmail.leidinger.net> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) X-OpenPGP-Key-Id: 0x89D8547E X-OpenPGP-Key-Fingerprint: 85EF E26B 07BB 3777 76BE B12A 9057 8789 89D8 547E MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: Alexander Leidinger , FreeBSD Hackers Subject: Re: Setting "zfs_arc_max" value in FreeBSD 8. X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 23 Jan 2010 02:40:04 -0000 On Fri, 22 Jan 2010 11:47, fbsdlist@ wrote: >>> Anyone know if it is adjustable on a system with 1024MB of ram ? Is this >>> just being auto calculated by some other value ? > > You may want to make sure that vm.kmem_size is set to a value much > larger than vfs.zfs.arc_max. Default value may be too small to allow > such a large ARC. > > On a side note, I'm not sure that ZFS is a good match for system with > only 1G of RAM. By trial and error on my box with 8G or memory I've > figured out that I need to set arc_max ~1G below physical memory size > to avoid lockups under load. YMMV. > ZFS on this box with 1G has been quite enjoyable actually. With the settings I have posted I have not had any lockup on stable/7 and no sudden freezes or waits for transfers. So this entirely thus far has been a godsend. I had even put this thing through some of the tortures that others have posted to the list and not come up with the same results but better. There is obviously a lot of variables in this between hardware and configurations used so the results are minimal in comparison. With ZFS in place on this machine it performs a little bit under specs for the hardware but I wouldn't expect anything less for such a file-system. -- Thoughts & Prayers out to Haiti. jhell