1 Million users.. I can't Scale!!

[Jeff Schwab]

skip at pobox.com wrote:
>     Jeff> How many are more than "a few?"
> 
> I don't know.  What can you do today in commercial stuff, 16 processors?
> How many cores per die, two? Four?  We're still talking < 100 processors
> with access to the same chunk of memory.  For the OP's problem that's still
> 10,000 users per processor.  Maybe that's small enough, but if not, he'll
> need multiple processes across machines that don't share memory.

Sure, multiple machines are probably the right approach for the OP; I 
didn't mean to disagree with that.  I just don't think they are "the 
only practical way for a multi-process application to scale beyond a few 
processors," like you said.  For many (most?) applications in need of 
serious scalability, multi-processor servers are preferable.  IBM has 
eServers available with up to 64 processors each, and Sun sells E25Ks 
with 72 processors apiece.  I like to work on those sorts of machine 
when possible.  Of course, they're not right for every application, 
especially since they're so expensive.