How to Investigate High Memory Use on a Linux Web Server

Linux may use otherwise free memory for cache, so a high used-memory number alone does not prove a server is under pressure. Look at available memory, swap activity, out-of-memory events, and application response time. A web server with a growing worker pool or memory leak needs a different fix from a host using memory for reclaimable cache.

Capture the system state

Compare free -h, process-level memory, swap-in and swap-out activity, and kernel logs during the slowdown. Track which processes grow over time and whether the increase follows traffic, a scheduled job, or a deployment. Confirm that monitoring samples are frequent enough to catch short spikes.

• Check web and PHP worker limits against observed concurrency.
• Review database buffers and application memory use together.
• Look for OOM-killer events and service restarts.
• Test a controlled worker or cache adjustment and measure the result.

Informatix Systems lists hosting and server management services. A capacity review can correlate system memory with application demand and service reliability. Contact Informatix Systems to investigate recurring server memory pressure.