From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brown Subject: Re: high throughput storage server? Date: Tue, 15 Feb 2011 10:43:56 +0100 Message-ID: References: <20110215044434.GA9186@septictank.raw-sewage.fake> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110215044434.GA9186@septictank.raw-sewage.fake> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 15/02/2011 05:44, Matt Garman wrote: > On Mon, Feb 14, 2011 at 06:06:43PM -0800, Doug Dumitru wrote: > > I'll also add that this NAS needs to be optimized for *read* > throughput. As I mentioned, the only real write process is the > daily "harvesting" of the data files. Those are copied across > long-haul leased lines, and the copy process isn't really > performance sensitive. In other words, in day-to-day use, those > 40--50 client machines will do 100% reading from the NAS. > If you are not too bothered about write performance, I'd put a fair amount of the budget into ram rather than just disk performance. When you've got the ram space to make sure small reads are mostly cached, the main bottleneck will be sequential reads - and big hard disks handle sequential reads as fast as expensive SSDs. > > No. :) 72 SSDs sounds like fun; 550 spinning disks sound dreadful. > I have a feeling I'd probably have to keep a significant number > on-hand as spares, as I predict drive failures would probably be a > weekly occurance. > Don't forget to include running costs in this - 72 SSDs use a lot less power than 550 hard disks.