Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dWAUJ-0006Lc-0r for pgsql-performance@arkaria.postgresql.org; Fri, 14 Jul 2017 23:59:11 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84_2) (envelope-from ) id 1dWAUI-000828-Ai for pgsql-performance@arkaria.postgresql.org; Fri, 14 Jul 2017 23:59:10 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1dWASY-0004su-EQ for pgsql-performance@postgresql.org; Fri, 14 Jul 2017 23:57:22 +0000 Received: from cat-porwal-prod-mail1.catalyst.net.nz ([2404:130:4080::4]) by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1dWAST-0004mE-4z for pgsql-performance@postgresql.org; Fri, 14 Jul 2017 23:57:19 +0000 Received: from localhost (localhost [127.0.0.1]) by cat-porwal-prod-mail1.catalyst.net.nz (Postfix) with ESMTP id 39E2980444 for ; Sat, 15 Jul 2017 11:57:13 +1200 (NZST) X-Virus-Scanned: Debian amavisd-new at cat-porwal-prod-mail1.servers.catalyst.net.nz Received: from cat-porwal-prod-mail1.catalyst.net.nz ([127.0.0.1]) by localhost (cat-porwal-prod-mail1.servers.catalyst.net.nz [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id nn3YmlUgaxSv for ; Sat, 15 Jul 2017 11:57:12 +1200 (NZST) Received: from [192.168.1.64] (122-62-58-23.jetstream.xtra.co.nz [122.62.58.23]) (Authenticated sender: mark.kirkwood@catalyst.net.nz) by cat-porwal-prod-mail1.catalyst.net.nz (Postfix) with ESMTPSA id 121FB80416 for ; Sat, 15 Jul 2017 11:57:12 +1200 (NZST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=catalyst.net.nz; s=catalyst; t=1500076632; bh=zqBb0RDaaxUMOe4YAqMMrBD2unZDH3SuZaw+3oM1KPI=; h=Subject:To:References:From:Date:In-Reply-To; b=bl6CHRhFOqVBfVMvDdiOyijMa5sOnX2VVAG1okwVXfQQJonOZaSaDMqhhKDxhUxra khLAZqXZ9EC4fB6uz2OaLLD3TVZBP09kpO9jdbd35iQWrUj+qqKrfwzZle6ExsJHqI EJrL509Eu191ihc8YDL6XFMkA5CJSRsh13CtR4x8= Subject: Re: Very poor read performance, query independent To: pgsql-performance@postgresql.org References: From: Mark Kirkwood Message-ID: Date: Sat, 15 Jul 2017 11:57:11 +1200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org Thinking about this a bit more - if somewhat more blazing performance is needed, then this could be achieved via losing the RAID card and spinning disks altogether and buying 1 of the NVME or SATA solid state products: e.g - Samsung 960 Pro or Evo 2 TB (approx 1 or 2 GB/s seq scan speeds and 200K IOPS) - Intel S3610 or similar 1.2 TB (500 MB/s seq scan and 30K IOPS) The Samsung needs an M.2 port on the mobo (but most should have 'em - and if not PCIe X4 adapter cards are quite cheap). The Intel is a bit more expensive compared to the Samsung, and is slower but has a longer lifetime. However for your workload the Sammy is probably fine. regards Mark On 15/07/17 11:09, Mark Kirkwood wrote: > Ah yes - that seems more sensible (but still slower than I would > expect for 5 disks RAID 0). -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance