Received: from maia.hub.org (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id CC262635AED for ; Tue, 9 Mar 2010 10:30:08 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 83926-02-4 for ; Tue, 9 Mar 2010 14:29:57 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from mx3.uci.cu (ns3.uci.cu [200.55.140.180]) by mail.postgresql.org (Postfix) with SMTP id A806263416B for ; Tue, 9 Mar 2010 10:29:56 -0400 (AST) Received: (qmail 26355 invoked by uid 507); 9 Mar 2010 14:29:47 -0000 Received: from 10.0.0.183 by ns3.uci.cu (envelope-from , uid 501) with qmail-scanner-2.01st (avp: 5.0.2.0. spamassassin: 3.0.6. perlscan: 2.01st. Clear:RC:1(10.0.0.183):. Processed in 0.666699 secs); 09 Mar 2010 14:29:47 -0000 Received: from unknown (HELO ucimail2.uci.cu) (10.0.0.183) by 0 with SMTP; 9 Mar 2010 14:29:47 -0000 Received: from localhost (localhost.localdomain [127.0.0.1]) by ucimail2.uci.cu (Postfix) with ESMTP id 5E2563DC257; Tue, 9 Mar 2010 09:31:39 -0500 (CST) X-Virus-Scanned: amavisd-new at uci.cu Received: from ucimail2.uci.cu ([127.0.0.1]) by localhost (ucimail2.uci.cu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id WWU-6JmnwFaL; Tue, 9 Mar 2010 09:31:35 -0500 (CST) Received: from [10.36.18.44] (unknown [10.36.18.44]) by ucimail2.uci.cu (Postfix) with ESMTP id 426533DC04C; Tue, 9 Mar 2010 09:31:35 -0500 (CST) Message-ID: <4B965C63.6040305@uci.cu> Date: Tue, 09 Mar 2010 09:34:11 -0500 From: "Ing. Marcos Ortiz Valmaseda" User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Pierre C CC: Greg Smith , Scott Carey , "" , Scott Marlowe , Francisco Reyes , Pgsql performance Subject: Re: 10K vs 15k rpm for analytics References: <06A22EB5-2D84-401C-B75F-7CA883695E0A@richrelevance.com> <4B95F222.6040504@2ndquadrant.com> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0.001 tagged_above=-10 required=5 tests=BAYES_50=0.001 X-Spam-Level: X-Archive-Number: 201003/90 X-Sequence-Number: 37915 Pierre C escribió: > On Tue, 09 Mar 2010 08:00:50 +0100, Greg Smith > wrote: > >> Scott Carey wrote: >>> For high sequential throughput, nothing is as optimized as XFS on >>> Linux yet. It has weaknesses elsewhere however. >>> > > When files are extended one page at a time (as postgres does) > fragmentation can be pretty high on some filesystems (ext3, but NTFS > is the absolute worst) if several files (indexes + table) grow > simultaneously. XFS has delayed allocation which really helps. > >> I'm curious what you feel those weaknesses are. > > Handling lots of small files, especially deleting them, is really slow > on XFS. > Databases don't care about that. > > There is also the dark side of delayed allocation : if your > application is broken, it will manifest itself very painfully. Since > XFS keeps a lot of unwritten stuff in the buffers, an app that doesn't > fsync correctly can lose lots of data if you don't have a UPS. > > Fortunately, postgres handles fsync like it should be. > > A word of advice though : a few years ago, we lost a few terabytes on > XFS (after that, restoring from backup was quite slow !) because a > faulty SCSI cable crashed the server, then crashed it again during > xfsrepair. So if you do xfsrepair on a suspicious system, please image > the disks first. > And then Which file system do you recommend for the PostgreSQL data directory? I was seeying that ZFS brings very cool features for that. The problem with ZFS is that this file system is only on Solaris, OpenSolaris, FreeBSD and Mac OSX Server, and on Linux systems not What do you think about that? Regards -- -------------------------------------------------------- -- Ing. Marcos Luís Ortíz Valmaseda -- -- Twitter: http://twitter.com/@marcosluis2186 -- -- FreeBSD Fan/User -- -- http://www.freebsd.org/es -- -- Linux User # 418229 -- -- Database Architect/Administrator -- -- PostgreSQL RDBMS -- -- http://www.postgresql.org -- -- http://planetpostgresql.org -- -- http://www.postgresql-es.org -- -------------------------------------------------------- -- Data WareHouse -- Business Intelligence Apprentice -- -- http://www.tdwi.org -- -------------------------------------------------------- -- Ruby on Rails Fan/Developer -- -- http://rubyonrails.org -- -------------------------------------------------------- Comunidad Técnica Cubana de PostgreSQL http://postgresql.uci.cu http://personas.grm.uci.cu/+marcos Centro de Tecnologías de Gestión de Datos (DATEC) Contacto: Correo: centalad@uci.cu Telf: +53 07-837-3737 +53 07-837-3714 Universidad de las Ciencias Informáticas http://www.uci.cu