suspend on SSD as fast as on mechanical HD Was : Re: SSD alignment for debian

[berenger.morel@neutralite.org]

Le 22.12.2012 15:10, Hugo Vanwoerkom a écrit :
> Daniel Dalton wrote:
> > Hello,
> > I've installed debian with a separate /home partition on my samsung 
> > 830
> > series ssd drive.
> > I would like to verify partition alignment is correct though.
> > Could someone tell me how to verify this or let me know if it is
> > correct?
>
> <skip>
>
> I have the same SSD. Surprise: doing a suspend to disk to that swap
> file you have on it makes no difference at all! Just as slow as to a
> regular HDD. Why?
>
> Hugo

AFAIK, speed difference between SSD and mechanical HD is mostly due to 
the fact SSD have fast random access.
When you suspend on disk, you write huge amount of data in a single 
location of the disk, so the need of mechanical moves become slightly 
less problematic.
That's why on FAT, defragmentation is very important to fasten HD 
access.

Of course, it depends on the controller's speed.

Another possibility would be that linux writes data in swap regularly, 
so there are not so many things to write when you suspend/hibernate.