From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Campbell Subject: Re: raid5 code ok with 2TB + ? Date: Sun, 28 Nov 2004 23:20:12 +0400 Message-ID: <41AA24EC.5020206@wasp.net.au> References: <200411281819.iASIJmN00402@www.watkins-home.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200411281819.iASIJmN00402@www.watkins-home.com> Sender: linux-raid-owner@vger.kernel.org To: Guy Cc: 'Stephan van Hienen' , linux-raid@vger.kernel.org List-Id: linux-raid.ids Guy wrote: > Your 2.2T array is not as big as you think! > > 1TB = 2^40 not 1*10^12 > Maybe depending on if you are buying disk drives, or selling them! :) > But when related to the 2TB limit it is 2^40. > > 2206003968 blocks > Divide by 1024 gives you 2154300.75 meg > Divide by 1024 gives you 2103.8093 Gig > Divide by 1024 gives you 2.0545 TB > So you are just over 2TB. by 58520320 blocks or 55.8 Gig. > > The only reason I am being exact is that you have not tested disk I/O beyond > 2TB as much as you think. Once, someone else made a similar 2T claim, after > the math he was really below 2T. Fair call. Having said that, if the code wrapped at 2TB then I would have blown away the 1st 55.8 Gig of my partition, which would be enough to prove the code faulty :p) -- Brad /"\ Save the Forests \ / ASCII RIBBON CAMPAIGN Burn a Greenie. X AGAINST HTML MAIL / \