Re: Calculating optimal disk partitions

[Chris Murphy]

On May 14, 2013, at 8:29 AM, address@hidden wrote:

> On Saturday, May 11, 2013 04:14, "Chris Murphy" <address@hidden> said:
>> So again the best
>> option is specifying the first partition start sector of 2048 (i.e. 1MB), 
>> and from
>> there in whole MB increments. 


> If I understand you regarding HDDs, they all have a logical sector size of 
> 512 bytes (which, BTW, is consistent with my experience)?

There are 4Kn HDDs which are 4096 byte logical and physical sector disks. 
Whether 512/512, 512/4096, or 4096/4096, if you align on 1MB boundaries, you're 
fine.


> And the first partition should start at sector 2048, with subsequent sector 
> starts should be multiples of 8?

If you align on whole MB boundaries, it's an easier and more universal 
solution. Yes technically on a 512e HDD you're also fine aligning on 8 
(logical) sector boundaries.


> I assume the first 1MB is for the boot record and various partition 
> information?

It depends on the partition scheme. If it's MBR then only one 512 byte sector 
is used for partition information, the rest is often used for GRUB's core.img. 
For GPT, several sectors are used, so the rest is just unused space since 
there's a separate partition type for GRUB: BIOS Boot on BIOS hardware, and EFI 
System on UEFI hardware.

> If my assumptions are correct, then that makes things easy. Start the first 
> partition at sector 2048, and start subsequent partitions on multiples of 8.

1MB boundaries is even easier. 

Chris Murphy