From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brown Subject: Re: high throughput storage server? Date: Thu, 17 Feb 2011 11:39:10 +0100 Message-ID: References: <4D5A7198.7060607@hardwarefreak.com> <4D5C5EAA.3020208@hardwarefreak.com> <4D5C6F8E.9020802@hardwarefreak.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4D5C6F8E.9020802@hardwarefreak.com> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 17/02/2011 01:45, Stan Hoeppner wrote: > David Brown put forth on 2/16/2011 6:26 PM: > >> On 17/02/11 00:32, Stan Hoeppner wrote: > >>> RAID level space/cost efficiency from a TCO standpoint is largely irrelevant >>> today due to the low price of mech drives. Using the SATABeast as an example, >>> the cost per TB of a 20TB RAID 10 is roughly $1600/TB and a 20TB RAID 6 is about >>> $1200/TB. Given all the advantages of RAID 10 over RAID 6 the 33% premium is >>> more than worth it. > >> I don't think it is fair to give general rules like that. In this particular > > The IT press does it every day. CTOs read those articles. In many cases it's > their primary source of information. Speak in terms CTOs (i.e. those holding > the purse) understand. > I work at a small company - I get to read the articles, make the recommendations, and build the servers. So I can put more emphasis on what I think is technically the best solution for us, rather than what sounds good in the press. Of course, the other side of the coin is that being a small company with modest server needs, I don't get to play with 20 TB raid systems! >> case, that might be how the sums work out. But in other cases, using RAID 10 >> instead of RAID 6 might mean stepping up in chassis or controller size and >> costs. Also remember that RAID 10 is not better than RAID 6 in every way - a >> RAID 6 array will survive any two failed drives, while with RAID 10 an unlucky >> pairing of failed drives will bring down the whole raid. Different applications >> require different balances here. > > I'm not sure about being "fair" but it directly relates to the original question > that started this thread. The OP wanted performance and space with a preference > for performance. This demonstrates he can get the performance for a ~33% cost > premium. He didn't mention a budget limit, only that most vendor figures were > too high. > I agree that RAID 10 sounds like a match for the OP. All I am saying is that it is not necessarily the best choice in general, and not just because of the initial purchase price. > Also, you're repeating points I've made in this (and other) threads back to me. > Try to keep up David. ;) > I'm doing my best! I believe I've got a fair understanding of various sorts of RAID systems, but I am totally missing real-world experience of anything more advanced than a four disk setup. Bigger raid setups is only a hobby interest for me at the moment, so I'm learning as I go here. And you write such a lot here that it's hard for an amateur to take it all in :-)