From owner-freebsd-questions@FreeBSD.ORG Fri Sep 16 21:47:15 2011 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 4555D106564A for ; Fri, 16 Sep 2011 21:47:15 +0000 (UTC) (envelope-from terje@elde.net) Received: from keepquiet.net (keepquiet.net [IPv6:2a01:4f8:130:84c1::deaf:babe]) by mx1.freebsd.org (Postfix) with ESMTP id 05DE48FC14 for ; Fri, 16 Sep 2011 21:47:15 +0000 (UTC) Received: from [10.0.0.30] (13.80-203-88.nextgentel.com [80.203.88.13]) (using TLSv1 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (Client did not present a certificate) (Authenticated sender: terje@elde.net) by keepquiet.net (Postfix) with ESMTPSA id 28D072E1C8; Fri, 16 Sep 2011 23:47:11 +0200 (CEST) References: <20110916063153.200375qdq59crf8c@mail.top-consulting.net> <32990703-D068-4B0D-AF3A-C1E6EA0A4100@elde.net> <20110916101833.17485ybnq5srjbc4@mail.top-consulting.net> In-Reply-To: <20110916101833.17485ybnq5srjbc4@mail.top-consulting.net> Mime-Version: 1.0 (iPhone Mail 8C148) Content-Type: text/plain; charset=us-ascii Message-Id: <685DC833-382F-4AD6-B2F9-307645E7FB39@elde.net> Content-Transfer-Encoding: quoted-printable X-Mailer: iPhone Mail (8C148) From: Terje Elde Date: Fri, 16 Sep 2011 23:47:00 +0200 To: "freebsd@top-consulting.net" Cc: "freebsd-questions@freebsd.org" Subject: Re: FS of choice for max random iops ( Maildir ) 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: Fri, 16 Sep 2011 21:47:15 -0000 On 16. sep. 2011, at 16:18, freebsd@top-consulting.net wrote: > zpool create data da1 > zfs create data/maildomains > zfs set sync=3Ddisabled data/maildomains Just for the archives... sync=3Ddisabled won't disable disable the zil, it'l= l disable waiting for a disk-flush on fsync etc. With a battery backed contr= oller cache, those flushes should go to cache, and be pretty mich free. You e= nd up tossing away something for nothing.=20 You're getting about half the performance on a sequential write to the zfs, a= s you get with raw ufs. That makes perfect sense, doesn't it? Ufs writes raw, zfs writes to zil, then final restingplace forthe data. Acco= unt for the seeks between, and you're seeing what you should.=20 Move the zil if you don't want both those sets of writes on the same array, o= r do what Svein said, and get funk^w logical.=20 (a tad simplified, but I think the logic will hold. (yes, pun intended)) Terje=