From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brown Subject: Re: from 2x RAID1 to 1x RAID6 ? Date: Thu, 09 Jun 2011 15:42:22 +0200 Message-ID: References: <4DEE6A11.1030205@xunil.at> <4DEE84F0.2030205@harddata.com> <4DEEBB66.7080802@nybeta.com> <4DEF4AC5.1090003@anonymous.org.uk> <4DF0C81E.4020903@oldum.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4DF0C81E.4020903@oldum.net> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 09/06/2011 15:18, Nikolay Kichukov wrote: > -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 > > > > On 06/08/2011 01:33 PM, David Brown wrote: > >> So you install your RAID10 (or RAID6, if you prefer) system, and >> make sure you keep backups. And if you /do/ get hit by a double >> disk failure in the wrong place, you spend the day restoring >> everything from the backups. When management complain that a 24 >> hour downtime doesn't fit with their 99.99% uptime expectations, >> you remind them that this is amortized over the next 27 years... > > Hi David, > > nice one ;-) Did you actually calculate 24 hours for those 99.99% > within 27 years? ;-) > 27.4 years is 10,000 days - so you can have 99.99% uptime with a 24-hour failure if you run for the rest of the 27.4 years without a hitch. Of course, by the same logic you can claim 6 nine's uptime with a week's failure - as long as there are no more problems for the next 20,000 years... :-) > Cheers, - -Nik