2: Memory
Parkinson’s Law explains why RAM seems to be always shrinking – and the more is added, the more gets chewed up.
The Argent Rule LINUX_FREE_MEMORY_64M is effective at monitoring your Linux servers’ memory.
Because memory usage is the opposite to CPU, there is no need to test multiple times – memory slowly increases.
When this Rule does break, look for processes with memory leaks – Argent can recycle errant processes to provide an interim solution until the vendor corrects the bugs.