From owner-freebsd-fs@FreeBSD.ORG Tue May 29 21:04:28 2007 Return-Path: X-Original-To: freebsd-fs@freebsd.org Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id F08DF16A41F for ; Tue, 29 May 2007 21:04:28 +0000 (UTC) (envelope-from kris@obsecurity.org) Received: from elvis.mu.org (elvis.mu.org [192.203.228.196]) by mx1.freebsd.org (Postfix) with ESMTP id DC29213C4AD for ; Tue, 29 May 2007 21:04:28 +0000 (UTC) (envelope-from kris@obsecurity.org) Received: from obsecurity.dyndns.org (elvis.mu.org [192.203.228.196]) by elvis.mu.org (Postfix) with ESMTP id 934401A4D81; Tue, 29 May 2007 14:05:37 -0700 (PDT) Received: from rot13.obsecurity.org (rot13.obsecurity.org [192.168.1.5]) by obsecurity.dyndns.org (Postfix) with ESMTP id 438E5511A7; Tue, 29 May 2007 17:04:28 -0400 (EDT) Received: by rot13.obsecurity.org (Postfix, from userid 1001) id 2D749B990; Tue, 29 May 2007 17:04:28 -0400 (EDT) Date: Tue, 29 May 2007 17:04:28 -0400 From: Kris Kennaway To: St?le Kristoffersen Message-ID: <20070529210427.GA50838@rot13.obsecurity.org> References: <46487565.40205@tychl.net> <20070528231218.GA14746@eschew.pusen.org> <20070529185456.GA48827@rot13.obsecurity.org> <20070529202805.GB16557@eschew.pusen.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070529202805.GB16557@eschew.pusen.org> User-Agent: Mutt/1.4.2.2i Cc: freebsd-fs@freebsd.org, Kris Kennaway Subject: Re: ZFS performance 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, 29 May 2007 21:04:29 -0000 On Tue, May 29, 2007 at 10:28:05PM +0200, St?le Kristoffersen wrote: > On 2007-05-29 at 14:54, Kris Kennaway wrote: > > On Tue, May 29, 2007 at 01:12:18AM +0200, St?le Kristoffersen wrote: > > > On 2007-05-14 at 10:42, Nick Gustas wrote: > > > > I see the same behavior that St?le is seeing, I can "fix" it by setting > > > > vfs.zfs.prefetch_disable="1" in loader.conf. I'm assuming something in > > > > the prefetch code isn't quite right? > > > > > > Ah, this _greatly_ improved the usability of my fileserver! Thanks for the > > > tip :) > > > > How does filesystem performance change? I thought ZFS needs to do > > prefetching to improve read performance. > > How the performance changed was dramatically, it went from beeing about > useless for doing anything other than watching one stream from it, to > tackle several concurrent streams without problems. I whish prefetching > would work correctly, it should improve performance even more. Well, that is one aspect of performance, but prefetching is presumably important for other workloads. Kris