Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id 44C32632F5F for ; Tue, 10 Nov 2009 11:43:48 -0400 (AST) 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 93682-04 for ; Tue, 10 Nov 2009 15:43:27 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-iw0-f182.google.com (mail-iw0-f182.google.com [209.85.223.182]) by mail.postgresql.org (Postfix) with ESMTP id 10D5763284E for ; Tue, 10 Nov 2009 11:43:36 -0400 (AST) Received: by iwn12 with SMTP id 12so108830iwn.15 for ; Tue, 10 Nov 2009 07:43:34 -0800 (PST) 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; bh=bRbPT1cCYW4e5YCgSY3WoXQPWgEpTfaIYgEi6ld6a+A=; b=rFVY3vY2Aqnqc38fVVGseCEdKqaXgbjw2f1e3QJriCBDL6xpgOgPGOn5/2tTg9JRWf ZErtQOSainGmzhr6bsUNISTeKrAtIVMV8Ub58u4fBwbZqvCN7v81VIdfoABSye/OGNWO Vh52Dux4mAfDhkuQmIy6glHWVVo7K3OIbUVzY= 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; b=E76/clBcn6ZDCP5h1NZxUhIyFCO4J39UEmc2CB5mj8T2sPiYwGfGiiBM8zq43rM+SK BNlzMmwyViuVwkFtGmbWm19tTUDKnDt+cE2P9QdGrVbVfeFtyqNh0pfgGkl0jtnUVVrW GEl+AW78lWbEUmm7SzQIcWsKFENmr2E8oBJ0I= MIME-Version: 1.0 Received: by 10.231.28.143 with SMTP id m15mr385898ibc.23.1257867814730; Tue, 10 Nov 2009 07:43:34 -0800 (PST) In-Reply-To: <8a1bfe660911100700l2a44f638m97ea6136b65deb21@mail.gmail.com> References: <8a1bfe660911100355l34a557ffj8244079c1fb689b5@mail.gmail.com> <8a1bfe660911100700l2a44f638m97ea6136b65deb21@mail.gmail.com> Date: Tue, 10 Nov 2009 08:43:34 -0700 Message-ID: Subject: Re: limiting performance impact of wal archiving. From: Scott Marlowe To: Laurent Laborde Cc: Ivan Voras , pgsql-performance@postgresql.org Content-Type: text/plain; charset=ISO-8859-1 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-2.352 tagged_above=-10 required=5 tests=AWL=-0.068, BAYES_00=-2.599, SARE_MILLIONSOF=0.315 X-Spam-Level: X-Archive-Number: 200911/103 X-Sequence-Number: 36271 On Tue, Nov 10, 2009 at 8:00 AM, Laurent Laborde wrote: > > Desktop drive can easily do 60MB/s in *sequential* read/write. > We use high performance array of 15.000rpm SAS disk on an octocore > 32GB and IO is always a problem. How man drives in the array? Controller? RAID level? > I explain the problem : > > This server (doing wal archiving) is the master node of the > over-blog's server farm. > hundreds of GB of data, tens of millions of articles and comments, > millions of user, ... > ~250 read/write sql requests per seconds for the master > ~500 read sql request per slave. That's really not very fast.