From owner-freebsd-questions@FreeBSD.ORG Mon Sep 17 12:20:17 2012 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9575D106564A for ; Mon, 17 Sep 2012 12:20:17 +0000 (UTC) (envelope-from jamie@kode5.net) Received: from kontrol.kode5.net (kontrol.kode5.net [80.229.5.32]) by mx1.freebsd.org (Postfix) with ESMTP id 04FC58FC14 for ; Mon, 17 Sep 2012 12:20:16 +0000 (UTC) Received: from kontrol.kode5.net (localhost [127.0.0.1]) by kontrol.kode5.net (8.14.5/8.14.5) with ESMTP id q8HCKE3x036026 for ; Mon, 17 Sep 2012 13:20:15 +0100 (BST) (envelope-from jamie@kode5.net) Received: (from jamie@localhost) by kontrol.kode5.net (8.14.5/8.14.5/Submit) id q8HCKEqV036025 for freebsd-questions@freebsd.org; Mon, 17 Sep 2012 13:20:14 +0100 (BST) (envelope-from jamie@kode5.net) X-Authentication-Warning: kontrol.kode5.net: jamie set sender to jamie@kode5.net using -f Date: Mon, 17 Sep 2012 13:20:14 +0100 From: Jamie Paul Griffin To: freebsd-questions@freebsd.org Message-ID: <20120917122014.GC25763@kontrol.kode5.net> Mail-Followup-To: freebsd-questions@freebsd.org References: <20120917103632.GA25763@kontrol.kode5.net> <50570895.4030709@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50570895.4030709@gmail.com> x-operating-system: FreeBSD 9.1-PRERELEASE amd64 x-pgp-fingerprint: A4B9 E875 A18C 6E11 F46D B788 BEE6 1251 1D31 DC38 x-pgp-key: 1D31DC38 User-Agent: Mutt/1.5.21 (2010-09-15) X-Virus-Scanned: clamav-milter 0.97.5 at kontrol.kode5.net X-Virus-Status: Clean Subject: Re: Questions about ZFS Tuning 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: Mon, 17 Sep 2012 12:20:17 -0000 [ Volodymyr Kostyrko wrote on Mon 17.Sep'12 at 14:25:09 +0300 ] > Handbook is old and cripsy about that all thing yet provides a useful > link to http://wiki.freebsd.org/ZFSTuningGuide > > - you don't need kmem_size/arc tuning on amd64 generally; > - zfs.zfs.prefetch_disable=0 will cause system eat more RAM then > without it; > - there are a lot of tunables but you should learn what you are doing > before setting anything, for example changing recordsize for already > running MySQL database filesystem will do nothing at all. Yes, I've seen lot's of information about ZFS tunables on FreeBSD which will give me plenty of reading. I set zfs.zfs.prefetch_disable=0 because some dmesg line suggested/implied it would benefit. I don't recall the exact output now. So, I think it's probably best I just leave things as they are as my system is functioning well enough, as far as I can tell anyway. This is the first time I've used ZFS on FreeBSD so I am still very much in the 'learning process' where that is concerned. Thanks for your response Volodymyr. Very much appreciated. Best wishes, Jamie.