Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1Y0v7y-0008Dq-Ir for pgsql-performance@arkaria.postgresql.org; Tue, 16 Dec 2014 16:37:38 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1Y0v7x-0004Vu-Uz for pgsql-performance@arkaria.postgresql.org; Tue, 16 Dec 2014 16:37:37 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1Y0v7x-0004Vk-2G for pgsql-performance@postgresql.org; Tue, 16 Dec 2014 16:37:37 +0000 Received: from mail-wg0-x22a.google.com ([2a00:1450:400c:c00::22a]) by makus.postgresql.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:256) (Exim 4.80) (envelope-from ) id 1Y0v7t-0005pH-Lz for pgsql-performance@postgresql.org; Tue, 16 Dec 2014 16:37:35 +0000 Received: by mail-wg0-f42.google.com with SMTP id k14so1729329wgh.1 for ; Tue, 16 Dec 2014 08:37:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=content-type:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=cvBbV03nBNhCw5ZrMqzE6n0kgXi0eLDcY4bD2C7iWgo=; b=dgHY5mimYiKuO1msNMLiBAh32p9XGHL+0imV1JXNxfO5Qwv2L9vCTQEleiLakKiJdz fc05c37aSAT7iZTPlgk1/zCY3+/CxjO2jJZjQAIQYArxZ5Gqy2yAWO3MmzkqSADwiPVG Jw6v81/MfdB6xQBKy6VvIDU15EHWq6kEkwsW+0mzz3ZBWyYYmjKcgXu6dl3bgOm3Eq9e UZFyZHA0rKEvQ4Gudbxqrma6C4u3hmDHJTAd+q+wccJxTM0+w6a4US/mK28ChasKCp5r dORNWQqVxmVoXdDFDDxJC0sJhNCsRM5+VfCDC4JXGlLRPS9HrsWu4xUerKwRZgRhDQaF kCcg== X-Received: by 10.180.87.36 with SMTP id u4mr6277072wiz.20.1418747851923; Tue, 16 Dec 2014 08:37:31 -0800 (PST) Received: from wgaybook.corp.wargaming.local (by1-office.wargaming.net. [178.172.239.242]) by mx.google.com with ESMTPSA id p5sm17553210wix.7.2014.12.16.08.37.30 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 16 Dec 2014 08:37:31 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 8.0 \(1990.1\)) Subject: Re: Tuning the configuration From: Evgeniy Shishkin In-Reply-To: Date: Tue, 16 Dec 2014 19:37:28 +0300 Cc: Andrea Suisani , "mfatticcioni@mbigroup.it" , "pgsql-performance@postgresql.org" Content-Transfer-Encoding: quoted-printable Message-Id: <63042BAB-3B28-441F-B819-B2DDC8FB24EE@gmail.com> References: <548823F8.4070003@mbigroup.it> <548987D7.7040304@opinioni.net> <6B084BAC-82C6-410A-88D4-9CDC01DA8C09@gmail.com> To: "Graeme B. Bell" X-Mailer: Apple Mail (2.1990.1) X-Pg-Spam-Score: -2.7 (--) 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 > On 16 Dec 2014, at 14:51, Graeme B. Bell wrote: >=20 >>=20 >> I don't understand the logic behind using drives,=20 >> which are best for random io, for sequent io workloads. >=20 > Because they are also best for sequential IO. I get 1.3-1.4GB/second from= 4 SSDs in RAID or >500MB/s for single disk systems, even with cheap models= .=20 > Are you getting more than that from high-end spinning rust? I better use ssd for random iops when database doesn't fit in ram. For wal logs i use raid with bbu cache and couple of sas drives. --=20 Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance