Session database in memory, mirrored to another host for redundancy, and only events that need to be stored written to "slow" SSDs when I/O bandwidth permits.
I could bring my startup from 10 to 2 hosts and have better performance.
I suppose that's true, thanks for putting that in perspective.
The real problem is that gobs of RAM isn't _cheap_. I wish that DDR4 would make DDR3 less expensive, but as manufacturers switch to making DDR4, I expect the price to rise.
edit: Which is to say, I'd be happy if it became possible in the near future to get laptops with 48GB of of DD3 and junky Dell rackmounts with 256GB of RAM for today's prices of 16/64GB respectively.
There are also diminishing returns for the average user. My mother would notice an SSD, but probably not another 4 gigabytes of RAM. Her computer almost never hits the swap partition.
I could bring my startup from 10 to 2 hosts and have better performance.