Date: Wed, 31 Aug 2005 22:13:21 +1000 From: Norberto Meijome <freebsd@meijome.net> To: Glenn Dawson <glenn@antimatter.net> Cc: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Re: How to create *exactly* the same partitions in different disks Message-ID: <43159EE1.4080901@meijome.net> In-Reply-To: <6.2.3.4.2.20050831012652.03013490@cobalt.antimatter.net> References: <43155735.4050101@meijome.net> <6.2.3.4.2.20050831012652.03013490@cobalt.antimatter.net>
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Glenn Dawson wrote: > At 12:07 AM 8/31/2005, Norberto Meijome wrote: > > fdisk wants slices to start on a head boundary, and end on a cylinder > boundary. > > if you make start evenly divisible by the number of sectors per track, > and make size+start evenly divisible by sectors*heads, fdisk won't > change any of the numbers on you. > > So, for your disk: > > start / sectors = 332775 > you have size specified as 467427240, so: > (467427240 + 20964825) / (16 * 63) = 484515.9375 > fdisk will treat that as 484515 and do: > (16 * 63 * 484515) - 20964825 = 467426295 > and use that number as the new size. Thanks for the explanation :) > > This matches ad6. It would appear that ad4 had the start and end values > explicitly set causing it to come out with different numbers. Gotcha. ad6 , ad8 and ad10 (*) , the ones I sliced by hand, follow this rule. ad4 doesn't, which is the one that got created by sysinstall on the initial setup. I told it to create a slice of 10GB. So sysinstall doenst follow the rule? Am I missing something here? I guess i can move all of ad4s1 around to ad6s1, boot off ad6, rebuild ad4s1 and move back in... right? (*) FWIW, all four drives are exactly the same, so the only difference is how the slices were done. ad4: 238475MB <WDC WD2500JS-00MHB0 02.01C03> at ata2-master SATA150 ad6: 238475MB <WDC WD2500JS-00MHB0 02.01C03> at ata3-master SATA150 ad8: 238475MB <WDC WD2500JS-00MHB0 02.01C03> at ata4-master SATA150 ad10: 238475MB <WDC WD2500JS-00MHB0 02.01C03> at ata5-master SATA150 Beto
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