Running a Linux system without swap can provide predictable performance, especially in environments where disk-based memory is undesirable. However, removing swap also means that the operating system has fewer options when physical RAM becomes exhausted. Once available memory reaches a critical level, Linux may trigger an Out-Of-Memory (OOM) event and terminate one or more processes to recover memory. An unexpected OOM event can be confusing because the application that gets terminated is not necessarily the only process responsible for memory pressure. Diagnosing the problem requires looking at system memory, individual processes, kernel messages, and the timing of the failure. This article explains a practical approach to investigating OOM events on systems that operate without swap. Understanding What Happens During an …
