[knappador]

One reason big machines might make a comeback is the increasing capability putting off the super-linear cost growth into the realm of > 100GB in-memory or > 10TB on disk. CPU hasn't kept pace unless you consider GPGPU or Phi parts.

Super-linear disk cost back when disks were already atrociously slow compared to the rest of the machine have largely gone away with SSD's hitting huge capacities and tech like NVMe, solid state RAM modules, and Intel's upcoming Optane tech ensuring that more than ever, scaling horizontally can be put off way more than used to be possible.

If you look at scale-out vs scale-up for any applications that were disk limited, disk performance is now ridiculous - > 1GB/s and IOP's measured in 100's of thousands. I'm expecting a bit of a comeback for HA over HP. More than likely, your app can be served well by a single big machine that is well within the linear scaling regime, and you need several for durability and geo-availability.

[Johnny555]

Terabyte sized memory will soon be possible with Xeon (if not already), Amazon announced x1 instances with 2TB of RAM + 100 cores. They are using Xeon E7 CPU's:

https://aws.amazon.com/blogs/aws/ec2-instance-update-x1-sap-...

[lsc]

Oh yeah, supermicro has been selling dual-socket xeon boards with 1.5tb ram capacity for a while.

http://www.supermicro.com/products/motherboard/Xeon/C600/X10...

that thing takes Xeon e5-26xx v3 CPUs which are pretty middle of the road server chips; Nothing fancy. If you want to go quad-socket with E7 xeons or something, you can get even more ram in one box, but the E5 Xeons are dramatically more economical than the E7 xeons.

I mean, the linked motherboard would be money, sure, but it would be the sort of cash that my company would be able to come up with.