[Beowulf] Building a new cluster - seeking some advice

[Mark Hahn]

> if you pushed it it could lock up your system, but maybe adequate to
> keep your system from locking up if you run barely over, rarely.

we actually aim our cluster nodes to fail a job fast if the user code 
tries to use too much memory, rather than limp along at 50x slowdown.
I suppose that a bit harsh, but we also provide a wide range of 
GB/core configurations.

> with 8 GB flash memory holding the OS and several GB of userspace.  A
> whole new kind of thin.

certainly appealing for laptops and thin clients.  I think we're in a funny
stage wrt general desktops and up, though: if you want serious storage,
flash isn't even on the table.  but probably your serious storage should be 
over a fast network connection, rather than on the desktop or compute node.

> Built in would have certain advantages -- USB fobs are too easy to knock
> off and are regrettably slow.  For clusters I'm not sure -- they are

PATA/SATA-interface flash is accelerating, I think.  Intel just introduced
a building block for that, and other vendors have had somewhat obscure 
products out for a long time.  a flash-based "PATA-fob" seems reasonably
secure to me for this kind of minimal case.  2.5 and 3.5" form-factors for 
larger flash-based disks are also popular.