10.1 fresh install and 4k alignment

Mark Martinec Mark.Martinec+freebsd at ijs.si
Wed Nov 19 15:07:06 UTC 2014


>> Am 19.11.2014 um 15:50 schrieb Mark Martinec 
>> <Mark.Martinec+freebsd at ijs.si>:
>> 
>> I consider a sensible alignment nowadays to be '-a 1m' for any
>> GPT partition, including freebsd-boot. If one is very short on space
>> and not on an SSD, one may save 0.5 MB by aligning freebsd-boot
>> on -a 512k and everything else on '-a 1m':

Patrick M. Hausen wrote:
> Why the "not on an SSD" condition?

Because an SSD erase block is typically 1 MB in size, and it's not 
desirable
to let it shuffle around blocks holding a boot partition when managing
some unrelated space that happens to be in the same 1 MB region.

   Mark


Btw:
   "The Windows Disk Manager in Windows Vista and Windows 7 utilizes
    a new 1 MB partition alignment scheme" [1]

[1] 
http://en.wikipedia.org/wiki/Disk_partitioning#DOS.2C_Windows.2C_and_OS.2F2


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