From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Eric D. Mudama" Subject: Re: Playing with SATA NCQ Date: Sun, 29 May 2005 09:22:37 -0600 Message-ID: <311601c9050529082248cb4c63@mail.gmail.com> References: <20050526140058.GR1419@suse.de> <429793C8.8090007@gmail.com> <42979C4F.8020007@pobox.com> <42979FA3.1010106@gmail.com> <20050528121258.GA17869@suse.de> <4299BD23.6010004@gmail.com> <4299CD31.8020805@rtr.ca> <4299D08E.2020706@dtbb.net> Reply-To: "Eric D. Mudama" Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: Received: from rproxy.gmail.com ([64.233.170.197]:40630 "EHLO rproxy.gmail.com") by vger.kernel.org with ESMTP id S261340AbVE2PWj convert rfc822-to-8bit (ORCPT ); Sun, 29 May 2005 11:22:39 -0400 Received: by rproxy.gmail.com with SMTP id i8so988700rne for ; Sun, 29 May 2005 08:22:37 -0700 (PDT) In-Reply-To: <4299D08E.2020706@dtbb.net> Content-Disposition: inline Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tyler Cc: linux-ide@vger.kernel.org Today's 7200 RPM IDE drives are in the ~70-80 ops/sec range for full-stroke random reads or writes (assuming cache off for writes). NCQ can usually turn 70-80 into 120-140 ops/sec, because of a decrease in average seek distance and the near-elimination of rotational latency. If the array and filesystem is setup/tuned properly, these ops/sec performance increases should translate directly into array performance increases. --eric On 5/29/05, Tyler wrote: > How effective can NCQ be in a RAID5/RAID6 environment? If at all? > > I wouldn't think it would be.. but maybe i'm not seeing the forest for > the trees.. > > Regards, > Tyler. > - > To unsubscribe from this list: send the line "unsubscribe linux-ide" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >