Swapdruk

Swapdruk is a term used in computer system administration to describe the level of memory pressure that triggers the swap subsystem to move pages from RAM to disk. It reflects how aggressively an operating system relies on swap space to satisfy the memory needs of running processes. There is no universal formal definition, but it is commonly used to summarize the state of memory pressure in monitoring dashboards and incident reports.

Causes of high swapdruk include limited physical RAM, memory leaks or unusually large working sets, cache-intensive workloads, and contention among multiple processes or containers. Indicators of strong swapdruk are the presence of swapped-out pages, frequent swap-ins and swap-outs per second, rising I/O wait, and low free memory or cache.

Effects of sustained high swapdruk are degraded performance and latency due to disk I/O, possible thrashing, and reduced throughput for user-facing applications. Systems may respond slowly as the cost of swapping dwarfs the benefit of keeping pages in memory.

Management and mitigation strategies include adding physical RAM, reducing memory footprint by tuning applications or limiting resource usage, and adjusting memory management parameters such as swappiness or cache pressure. Other approaches include using faster storage, enabling compressed or in-memory swap technologies (for example, zram on Linux), or reorganizing workloads to reduce concurrent memory demand.

In Dutch IT usage, swapdruk is a descriptive term for memory pressure and swapping activity rather than a formal metric defined by a single standard. It is commonly used in performance monitoring and incident analysis.