From owner-freebsd-questions@FreeBSD.ORG Fri Sep 16 14:27:23 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 61365106564A for ; Fri, 16 Sep 2011 14:27:23 +0000 (UTC) (envelope-from svein-listmail@stillbilde.net) Received: from mail.stillbilde.net (d80.iso100.no [81.175.61.195]) by mx1.freebsd.org (Postfix) with ESMTP id E26748FC18 for ; Fri, 16 Sep 2011 14:27:22 +0000 (UTC) Received: from [192.168.12.4] (unknown [192.168.12.4]) (Authenticated sender: svein-listmail) by mail.stillbilde.net (Familien Skogens mail) with ESMTPSA id 603DF39834 for ; Fri, 16 Sep 2011 16:08:38 +0200 (CEST) Message-ID: <4E735861.3040302@stillbilde.net> Date: Fri, 16 Sep 2011 16:08:33 +0200 From: "Svein Skogen (Listmail account)" User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:6.0.2) Gecko/20110902 Thunderbird/6.0.2 MIME-Version: 1.0 To: freebsd-questions@freebsd.org References: <20110916063153.200375qdq59crf8c@mail.top-consulting.net> <32990703-D068-4B0D-AF3A-C1E6EA0A4100@elde.net> <20110916095745.872947fg6vym1vy8@mail.top-consulting.net> In-Reply-To: <20110916095745.872947fg6vym1vy8@mail.top-consulting.net> X-Enigmail-Version: 1.3.1 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig8D7E4D6D14FED212CD19F39A" 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 14:27:23 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig8D7E4D6D14FED212CD19F39A Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 16.09.2011 15:57, freebsd@top-consulting.net wrote: > Quoting Terje Elde : >=20 >> On 16. sep. 2011, at 12:31, freebsd@top-consulting.net wrote: >>> Right now I defined an entire array of 8TB ( all 16 disks ) separated= >>> in two pieces. 50 GB for FreeBSD to boot and the rest available to >>> configure as storage. >> >> ZFS will want to write to it's ZIL (zfs intent log) before writing to >> the final location of the data. Even if you're not waiting for the >> ZIL-write to disk (because of the controller ram), those writes will >> probably make it through to disk. That gives you twice as many writes >> to disk, and a lot more seek. >> >> If you want to take zfs for a proper spin, I'd like to sugget adding >> two small SSDs to the setup, mirrored by zfs. You can use those both >> for the ZIL, and also as cache, for the array. That's a fairly small >> investment these days, and I would be surprised if it didn't >> significantly improve performance, both for your benchmark, and real >> load. >> >> Note: you might be in trouble if you loose your ZIL, thus the doubling= >> up. I *think* you can SSD a cache without risking dataloss, but don't >> take my word for it. >> >> Terje >=20 > I know it's usually a big no-no but since I have the battery backed-up > write cache from the raid card, can't I just disable the ZIL entirely ?= No. However, you could allow the ZIL to be written to a logical disk with the battery-backed cache. //Svein --=20 --------+-------------------+------------------------------- /"\ |Svein Skogen | svein@d80.iso100.no \ / |Solberg =D8stli 9 | PGP Key: 0xE5E76831 X |2020 Skedsmokorset | svein@jernhuset.no / \ |Norway | PGP Key: 0xCE96CE13 | | svein@stillbilde.net ascii | | PGP Key: 0x58CD33B6 ribbon |System Admin | svein-listmail@stillbilde.net Campaign|stillbilde.net | PGP Key: 0x22D494A4 +-------------------+------------------------------- |msn messenger: | Mobile Phone: +47 907 03 575 |svein@jernhuset.no | RIPE handle: SS16503-RIPE --------+-------------------+------------------------------- A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing on usenet and in e-mail? ------------------------------------------------------------ Picture Gallery: https://gallery.stillbilde.net/v/svein/ ------------------------------------------------------------ --------------enig8D7E4D6D14FED212CD19F39A Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk5zWGYACgkQODUnwSLUlKTIXACgjJK/NgvHpk1V3JrVw8wY16ZP Q3IAoI2NhULyqnIsyp28QJ8wUjzA9EEI =UzHD -----END PGP SIGNATURE----- --------------enig8D7E4D6D14FED212CD19F39A--