Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id 1CF5F6358B5 for ; Wed, 1 Apr 2009 14:04:17 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 69163-02-2 for ; Wed, 1 Apr 2009 14:04:13 -0300 (ADT) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-ew0-f167.google.com (mail-ew0-f167.google.com [209.85.219.167]) by mail.postgresql.org (Postfix) with ESMTP id A63546357B9 for ; Wed, 1 Apr 2009 14:04:13 -0300 (ADT) Received: by ewy11 with SMTP id 11so204168ewy.19 for ; Wed, 01 Apr 2009 10:04:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=ig8ljEX9o/yHf+pdgW8hse6m/wWiOBSJctaYvI8B42U=; b=YY9pFNk60uC+cRkrN6YnQeSbCtICBQnXA5mOjgniOy9apDn0AL8AUwkabQ8YxNh2Zi P/k2U5Dnw0GHoIJ7vEzyDBarcjgQi5uT2TamRTNmkxWUc3USgeFx0uPZSAEOr+ZYNZYI hkYwP5VqPYINTo+2xWVgNsFRoaksrs7p8DoiE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=x9o3VFMU8I+UQdMkiLN2KfUq5/f8tnIStNHLEg6JUdjzD4CbNp8TC29AkH8/X6Hvzm UjDdcHNXLrVtz0fAIfFN3QgkYMPwNP1kQj69XbwF8+ILKqqbo9BzW1KqYtjh3hoBRiEL CL6FLL3qa6QJ/fPRJFIWMqENECk3Fk4QS5sJI= MIME-Version: 1.0 Received: by 10.210.22.16 with SMTP id 16mr4611556ebv.62.1238605452355; Wed, 01 Apr 2009 10:04:12 -0700 (PDT) In-Reply-To: References: <49D31E85.8050405@paradise.net.nz> <49D37CAA.6080100@ummon.com> <49D3932D.3080808@ummon.com> <49D39AFA.8000700@ummon.com> Date: Wed, 1 Apr 2009 11:04:12 -0600 Message-ID: Subject: Re: Raid 10 chunksize From: Scott Marlowe To: Matthew Wakeling Cc: "pgsql-performance@postgresql.org" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0.003 tagged_above=0 required=5 tests=AWL=0.003 X-Spam-Level: X-Archive-Number: 200904/17 X-Sequence-Number: 33384 On Wed, Apr 1, 2009 at 11:01 AM, Matthew Wakeling wro= te: > On Wed, 1 Apr 2009, Stef Telford wrote: >> >> =A0 Good UPS, a warm PITR standby, offsite backups and regular checks is >> "good enough" for me, and really, that's what it all comes down to. >> Mitigating risk and factors into an 'acceptable' amount for each person. >> However, if you see over a 2x improvement from turning write-cache 'on' >> and have everything else in place, well, that seems like a 'no-brainer' >> to me, at least ;) > > In that case, buying a battery-backed-up cache in the RAID controller wou= ld > be even more of a no-brainer. This is especially true in that you can reduce downtime. A lot of times downtime costs as much as anything else.