Eviction_policy default in Memcached 1.6.x: Predicting latency under concurrent writes

Goal

Determine how the default eviction strategy in Memcached 1.6.x affects latency when many clients issue write operations simultaneously.

Constraints

Configuration files omit the eviction_policy directive; the server is started with the standard 1.6.x binary and no custom patches.

Uncertainty

The official documentation does not state whether the default is LRU, random, or another algorithm, making it unclear how eviction decisions will behave under contention.

Questions

• Which eviction strategy does Memcached 1.6.x default to when eviction_policy is unspecified?
• In a high‑concurrency write scenario, how does this default choice influence operation latency and request blocking?
• Is there a configuration knob that can be set to explicitly choose an eviction policy to mitigate latency spikes?