From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Campbell Subject: Re: question about the best suited RAID level/layout Date: Fri, 05 Jul 2013 09:07:36 +0800 Message-ID: <51D61C58.2020207@fnarfbargle.com> References: <1372961877.8716.43.camel@heisenberg.scientia.net> <51D5EC8A.40509@turmel.org> <1372978687.5249.52.camel@fermat.scientia.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1372978687.5249.52.camel@fermat.scientia.net> Sender: linux-raid-owner@vger.kernel.org To: Christoph Anton Mitterer Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 05/07/13 06:58, Christoph Anton Mitterer wrote: > I'd have even one more question here: Has anyone experience with my idea > of intentionally running devices of different vendors (Seagate, WD, > HGST)... for resilience reasons?... Does it work out as I plan, or are > there any hidden caveats I can't see which make the resilience (not the > performance) worse? I've got both here. A large RAID-6 comprised entirely of single brand, single type consumer drives and a smaller RAID-10 built from a diverse selection. Both have had great reliability, so that's not really a good data point for you. What I *have* found over the years is the importance of weeding out early failures. Before I commit a disk to service, I subject it to a couple of weeks of hard work. I usually knock up a quick and dirty bash script with multiple concurrent instances of dd reading and writing to differing parts of the disk simultaneously, with a bonnie++ run for good measure. With all this going on at the same time the drive mechanism gets a serious workout and the drive stays warmer than it will in actual service. If I have the chance, I do all the drives simultaneously and preferably in the machine they are going to spend the next couple of years. If I can't do that, then I have a burn-in chassis built from a retired server that can do 15 at a time. This has proven quite effective in spotting the early life failures. I generally find (for consumer drives) if they pass this they'll last the 3 years of 24/7 I use them for before I replace them. My enterprise drives are a different story, and I have some here with just over 38k hours on them. I'll probably replace them for bigger drives before they ever fail. Regards, Brad