Server Overload Fix & PHP Optimization

My newly-redesigned product catalogue site has been crashing the virtual cloud server it lives on. The load climbs rapidly until the kernel’s OOM-killer steps in, MySQL gets shot down, and Apache stops responding. Early digging points to two likely culprits: MySQL’s OOM score is too high, making it the first service killed, and suPHP is adding unnecessary overhead as our current PHP handler.

What I need is a concise rescue and hardening job:
STEP 1.
• Diagnose the precise cause of the memory spikes and 100 % CPU events.
• Re-tune (or override) the OOM score so MySQL stays alive under pressure.

STEP 2.
• Migrate the site from suPHP to a more efficient handler such as PHP-FPM or FastCGI, with zero downtime.
• Verify database settings and query cache to be sure MySQL itself is not the bottleneck.
• Hand back a short report describing what was changed and why, plus any follow-up recommendations.

The stack is standard LAMP on a virtual cloud server, MySQL is the only database, and the site is code-based—no cPanel wizards. SSH root access is ready when we agree on the plan. Success is the server running steadily for 48 hours under simulated peak traffic without MySQL getting killed or the site slowing to a crawl.