[Beowulf] BIG 'ram' using SSDs - was single machine with 500 GB of RAM
Ellis H. Wilson III
ellis at cse.psu.edu
Wed Jan 9 12:06:14 PST 2013
On 01/09/2013 02:24 PM, Vincent Diepeveen wrote:
> 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
It was commensurate with what you put into the writing process.
> random latency is
> under 70 us (achieved) at SSD's, so doubting that is kind of
> nonsense. it's what you ACHIEVE.
Yea. You're right. Constantly spitting crazy nonsense:
> You mix that up now as that you can get with random reads a speed of
> 2.7 GB/s,
No, my assumption is that if the poster says he needs tons of RAM, his
application probably has a random-access pattern. You harping on
sequential throughput is not constructive to the conversation, unless
you have identified the workload for the application is indeed
sequential via tracing.
> Writes really isn't the problem at hardware that has lots of parallel
They can be easier, as the publication above points out, but they still
are bound by the nature of MLC being slower at the device-level for
writes than reads. This is particularly for write-in-place and
random-writes, which I suspect this workload may have enough of to worry
> Maybe you should do some effort to read better. You would also have
> 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.
Oh, sorry, I assumed we were still having a constructive conversation
about the posters topic to help him achieve his goal for his application
rather than merely thread-stealing and upping the storage size by 10X
because "500GB is total peanuts." I'll remember to keep my measuring
stick handy next time I think about trying to help somebody build a
machine specific to their problem so I don't accidentally stumble into
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