Another way to watch for serious memory issues is by monitoring the OOMKiller spawning in your logs. This process is responsible for terminating processes in an effort to increase the available memory to a system when it’s under high pressure. Grepping for killed process in your syslog will spot this. I recommend creating an alert in your log management system for any occurrences of OOMKiller. Any time the OOMKiller is coming into the picture, you’ve got a problem somewhere, especially because OOMKiller is unpredictable in its choice of target processes to terminate.
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