[Beowulf] BIG 'ram' using SSDs - was single machine with 500 GB of RAM

Vincent Diepeveen diep at xs4all.nl
Wed Jan 9 11:24:54 PST 2013


On Jan 9, 2013, at 8:02 PM, Ellis H. Wilson III wrote:
>
> Yea, it's computer science, and I'd love to see you try to toss 16
> crappy SSDs in a box with a crappy RAID controller and get this easy
> 2.7GB/s random accesses you are touting.  Not going to happen.
>

If you had done effort reading what i wrote - i had said that the  
random latency is
under 70 us (achieved) at SSD's, so doubting that is kind of  
nonsense. it's what you ACHIEVE.

And i wrote that if the workload needs a tad of bandwidth, that you  
can easily achieve 2GB/s,
in fact that the raid controllers can achieve easily 2.7GB/s bandwidth.

You mix that up now as that you can get with random reads a speed of  
2.7 GB/s,
which is a very naive way of looking at it.

Writes really isn't the problem at hardware that has lots of parallel  
channels.

Maybe you should do some effort to read better. You would also have  
noticed then that
i started a new subject here. Namely not being busy with 500GB.

500GB is total peanuts. Cheapskate oldie 4 socket AMD box with 500GB  
and done.
No need to discuss even, as intel is too expensive simply at that  
range, not to mention IBM.

More interesting is the discussion in the many Terabyte range what to  
do there, as there will
be many alternatives where intel and IBM and others want to have to  
say something about i bet.

Thanks,
Vincent


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