From owner-freebsd-hardware@FreeBSD.ORG Thu Jan 8 08:13:30 2009 Return-Path: Delivered-To: freebsd-hardware@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8D2F110656C0 for ; Thu, 8 Jan 2009 08:13:30 +0000 (UTC) (envelope-from kgysmits@gmail.com) Received: from mail-bw0-f20.google.com (mail-bw0-f20.google.com [209.85.218.20]) by mx1.freebsd.org (Postfix) with ESMTP id D53B48FC1A for ; Thu, 8 Jan 2009 08:13:29 +0000 (UTC) (envelope-from kgysmits@gmail.com) Received: by bwz13 with SMTP id 13so355477bwz.19 for ; Thu, 08 Jan 2009 00:13:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type:references; bh=47Cgxh67xr351wKdymHuwkVoxum4jzShpVAQkq8YnbI=; b=hD0AuexoGEirHbdGS3DrNXb9VgSMVif9ehuxsygzLCZQxysh02nFhhv9V1LWwRa/mE LKBjTXJdzv2++AUkTMVzG0synsxvXw6vpB7ktlTO4asqEwCGb2JQut49cV2N11ez91mY t9yc6e/Vrm6KAdBTX0FniZzICpvADa0uxvUhQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:references; b=pF3YSpgyUdnVpm8pcLz1L8G7JMVKy/xtzpwNsEs57gXa12c62sukUCU7grOweq+SHA +DrsehtaGQTxd7CMByCSuA0j1hfgxLXrWZGxvs4GoEK5SGMlbCrEjbwQXHA0V1hm8YeU v2OOU7LyLWl5enbFr1OdKRhtSQgXp+eHNpOn4= Received: by 10.223.114.68 with SMTP id d4mr17236566faq.86.1231400913955; Wed, 07 Jan 2009 23:48:33 -0800 (PST) Received: by 10.223.108.136 with HTTP; Wed, 7 Jan 2009 23:48:33 -0800 (PST) Message-ID: Date: Thu, 8 Jan 2009 08:48:33 +0100 From: "Koen Smits" To: fbsd@dannysplace.net In-Reply-To: <496549D9.7010003@dannysplace.net> MIME-Version: 1.0 References: <20081031033208.GA21220@icarus.home.lan> <490A8FAD.8060009@dannysplace.net> <491BBF38.9010908@dannysplace.net> <491C5AA7.1030004@samsco.org> <491C9535.3030504@dannysplace.net> <4920E1DD.7000101@dannysplace.net> <20081117070818.GA22231@icarus.home.lan> <496549D9.7010003@dannysplace.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-fs@freebsd.org, Jeremy Chadwick , freebsd-hardware@freebsd.org Subject: Re: Areca vs. ZFS performance testing. X-BeenThere: freebsd-hardware@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: General discussion of FreeBSD hardware List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 Jan 2009 08:13:31 -0000 > One thing I am at a loss to understand is why turning off the disk > caches when testing the JBOD performance produced almost identical (very > slightly better) results. Perhaps it was a case of the ZFS internal > cache making the disks cache redundant? Comparing to the ARECA > passthrough (where the areca cache is used) shows again, similar results. > > -D > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" My guess is it probably has to do with the way ZFS does cache flushes: http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide#Cache_Flushes It might be worth it to disable the forced flushing and test again, if you feel like it. -Koen