X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 11884DBF48 for ; Sun, 27 Nov 2005 11:48:02 -0400 (AST) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 43888-08 for ; Sun, 27 Nov 2005 11:48:02 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from megazone.bigpanda.com (megazone.bigpanda.com [64.147.171.210]) by svr1.postgresql.org (Postfix) with ESMTP id A1248D7798 for ; Sun, 27 Nov 2005 11:47:59 -0400 (AST) Received: by megazone.bigpanda.com (Postfix, from userid 1001) id CFEF4356C6; Sun, 27 Nov 2005 07:48:01 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by megazone.bigpanda.com (Postfix) with ESMTP id CE6D635163; Sun, 27 Nov 2005 07:48:01 -0800 (PST) Date: Sun, 27 Nov 2005 07:48:01 -0800 (PST) From: Stephan Szabo To: Luke Lonergan Cc: dlang@invendra.net, pgsql-performance@postgresql.org Subject: Re: Hardware/OS recommendations for large databases ( In-Reply-To: <3E37B936B592014B978C4415F90D662DE11EBC@MI8NYCMAIL06.Mi8.com> Message-ID: <20051127072933.Q62040@megazone.bigpanda.com> References: <3E37B936B592014B978C4415F90D662DE11EBC@MI8NYCMAIL06.Mi8.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0 required=5 tests=[none] X-Spam-Score: 0 X-Spam-Level: X-Archive-Number: 200511/529 X-Sequence-Number: 15786 On Sun, 27 Nov 2005, Luke Lonergan wrote: > Has anyone done the math.on the original post? 5TB takes how long to > scan once? If you want to wait less than a couple of days just for a > seq scan, you'd better be in the multi-gb per second range. Err, I get about 31 megabytes/second to do 5TB in 170,000 seconds. I think perhaps you were exaggerating a bit or adding additional overhead not obvious from the above. ;) --- At 1 gigabyte per second, 1 terrabyte should take about 1000 seconds (between 16 and 17 minutes). The impressive 3.2 gigabytes per second listed before (if it actually scans consistently at that rate), puts it at a little over 5 minutes I believe for 1, so about 26 for 5 terrabytes. The 200 megabyte per second number puts it about 7 hours for 5 terrabytes AFAICS.