[Nottingham] SSD upgrade

[Martin]

On 11/02/14 13:19, Martin wrote:
> On 11/02/14 12:59, Jason Irwin wrote:
>> On 11/02/14 12:55, Martin wrote:
>>> Rather than waste time with Marketing games and ignorance, just assume
>>> 16MiB or if you're really keen, pull off the covers and look up the
>>> flash chip numbers... :-)
>> Just got it and don't want to break it on the second day!
> 
> You shouldn't be able to do it any harm by just merely writing to it.
> 
> Keep it away from pets and any children ;-)
> 
> 
> And for the alignment... Don't worry too much about that. The really
> important alignment is to ensure 4kB alignment for the 'sectors'.

Note that has been done automatically for everything Linux systems for
years now! The user need not be aware. It just simply works (tm :-) )


> Another sweet-spot is to use an aligned filesystem that works in 8kB or
> 16kB chunks (btrfs has just moved to 16kB for improved performance).
> 
> And, when aligning, you are fine to align to any multiple of whatever
> the aligning unit is. So assuming 16MiB for your partitions is a good
> idea and can't hurt regardless of whether that alignment can actually be
> for your device 256kB or 512kB for professional expensive devices or
> 2MiB or 4MiB for present "consumer grade" stuff.
> 
> 
> Enjoy the aligned speedup!
> 
> Have fun,
> Martin
> 
> 
> ps: No, SSDs do not physically have any HDD-style sectors, but that
> style of operation is assumed throughout the software stack still!
> 
> ps2: The next development may well be moving to 'RAM + FLASH' modules
> whereby the CPU accesses both system RAM /and/ flash storage all as one
> continuous address space... That could eliminate the SATA bottleneck.



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