I've watched team after team get surprised that their app gets substantially slower when they use up nearly all of the memory on the servers.
They look at the free memory and think, "wow look at all that free space, I can totally take up half of that no problem".
The moment the collective working set exceeds total memory things go sideways. They learn that the performance of the system tanks when there's not enough space left for OS-level caches and especially for memory mapped files.
They look at the free memory and think, "wow look at all that free space, I can totally take up half of that no problem".
The moment the collective working set exceeds total memory things go sideways. They learn that the performance of the system tanks when there's not enough space left for OS-level caches and especially for memory mapped files.