Re: Calculating optimal disk partitions

[craig]

On Saturday, May 11, 2013 04:14, "Chris Murphy" <address@hidden> said:

> 
> On May 10, 2013, at 1:00 PM, Ulf Zibis <address@hidden> wrote:
> 
>> Hi,
>>
>> Am 10.05.2013 04:52, schrieb Chris Murphy:
>>> The simplest rule of thumb is to start a partition at 1MB, and specify all
>>> partition sizes in whole MB's. It solves this, and maybe also for SSDs. The 
>>> open
>>> question is some SSDs have 2+MB erase block sizes and it's not clear if 
>>> there's
>>> a benefit, or even a way, to partition on 2MB boundaries. Any recent 
>>> partition
>>> tool starts the first partition on a 1MB boundary.
>>
>> Isn't it possible to to give more choice in the dialogue?
>> I also curious about the internal calculation for "what is optimal".
> 
> For HDD the only concern is for 512e drives, and it's very simple, aligning 
> on 8
> logical sectors equates to the file system blocks aligning to physical 
> sectors.
> 
> For SSD it's not so simple because manufacturer's are all doing different 
> things
> and optimizations in firmware, but not documenting any of it. So again the 
> best
> option is specifying the first partition start sector of 2048 (i.e. 1MB), and 
> from
> there in whole MB increments. And by MB I actually mean MiB.
> 
> 
> Chris Murphy

Hi Chris,

If I understand you regarding HDDs, they all have a logical sector size of 512 
bytes (which, BTW, is consistent with my experience)? And the first partition 
should start at sector 2048, with subsequent sector starts should be multiples 
of 8? I did find over the weekend, on another HDD, that sector starts that are 
multiples of 2048 work with no errors, and I was able to partition an entire 
drive into two primary partitions, and one extended partition containing two 
logical drives, with no unused space other than the initial 1MB. I assume the 
first 1MB is for the boot record and various partition information?

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.

Thanks for you help,
Craig



Sent - Gtek Web Mail