Our servers usually sit around all day at and ~25% Memory, but when I customer demands it, quickly (unscheduled and without prior notice) ramp up to use all memory available to it.
This makes the servers somewhat unstable. The simplest solution would be to simply upgrade the servers, but that would mean spending a lot of money for a server that only requires those additional resources for a few hours a week.
I've been looking for a solution that'll let me have a pool of virtual servers, each with a base level of memory and a pool of shared memory to be used by whichever of those servers needs it.
There are plenty of hosting providers offering VPS with "soft"/"burst" RAM, but none which let me manage this soft RAM in a pool of VPS so I can specify how much is available for each. Amazon can't change resources of an instance while running and due to security requirements I can't have our sites hosted on a large server with a single OS instance.
Does anybody know if a hosting solution exists or different solutions to such a problem?