Periodically, as with any large online service, we evaluate the current load on our hardware, and make attempts at "right-sizing" so that we're not paying for severely underutilized hardware.
How concerned should I be when factoring cache memory in use? It's my understanding that cache is by and large used as an optimization, but I seem to recall also reading that cache could stay held for a while beyond needing to be used -- a sort of waste due to excessively available resources. Here's an example of one of our current systems:
So my question then is, how "safe" should I play it when considering how much load this host can (or should) hold? Do I consider everything, used/buffers/cache, as 100% required for optimal use? Or can I be more lenient with cache, and assume the system may swap out cache entries more frequently, but not to a point that would actually cause application performance issues?
free -m, copy and paste the terminal output into your questions. The graphics are hard to read.