From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Scobie Subject: SAS v SATA interface performance Date: Sat, 01 Dec 2007 08:19:19 +1300 Message-ID: <47506237.3000406@clear.net.nz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.sauce.co.nz ([210.48.49.72]:47000 "EHLO smtp.sauce.co.nz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754902AbXK3T1P (ORCPT ); Fri, 30 Nov 2007 14:27:15 -0500 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: linux-ide@vger.kernel.org If one disregards the rotational speed and access time advantage that SAS drives have over SATA, does the SAS interface offer any performance advantage? For example, assume a SAS drive and a SATA drive can both sustained stream 70MB/s. A 16 drive JBOD SAS enclosure with internal SAS expander is connected via a 4port SAS RAID controller, configured for RAID 5 across all 16 drives. If tests are then run reading and writing a multi gigabyte file to empty arrays made up of 16 SAS drives and 16 SATA drives, would the results be identical? I ask, as I have seen a comment to the effect that SATA drives are less efficient interacting at the bus/interface level in this situation, but I have had no luck confirming this after extensive searching. Regards, Richard