Preparing a Site for Traffic Spikes
Product launches, big campaigns, and seasonal sales are great problems to have. They are also when websites fail in the most public way. This guide shows how you should be preparing a site for traffic spikes with three levers that matter most: caching, database tuning, and job queues.
Target outcome when you prepare site for traffic spikes
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Stable p95 response time under load
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Zero checkout or form failures
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No timeouts from external services
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Clear visibility into errors and bottlenecks
Two-week prep timeline while preparing a site for traffic spikes
T minus 14 to 10 days
Baseline performance, freeze scope, and convert any pseudo cron to real cron if applicable.
T minus 9 to 5 days
Implement edge and page caching, add Redis object cache, enable DB slow query logging, and move noncritical work to a queue.
T minus 4 to 2 days
Load test, tune PHP-FPM and DB limits, and prewarm caches.
T minus 1 day
Final health check, on-call plan, and a content freeze with a simple release checklist.
Day of event
Watch p95 latency, error rate, queue depth, and DB connections. Scale carefully with small, reversible changes.
Caching: the fastest way on preparing a site for traffic spikes
Edge and CDN caching
Cache HTML for anonymous traffic at the edge where you can. Use cache keys and sensible TTLs with stale-while-revalidate so cold misses do not cascade.
Helpful background: MDN Cache-Control, Cloudflare CDN basics. This should help you while preparing a site for traffic spikes
Bypass rules for ecommerce
Do not cache cart, checkout, or account pages. Bypass when session or cart cookies are present. Let API endpoints stay dynamic.
Application-level page cache
If your platform supports it, serve generated HTML from disk or memory. Prewarm top landing pages an hour before launch. See Google’s guidance on speed outcomes: web.dev Core Web Vitals.
Object caching with Redis
Dynamic sites rely on repeated DB reads. An object cache stores results in memory to avoid duplication of work. Aim for a 90 percent hit ratio during peak.
Learn more: Redis overview.
Opcode cache
Ensure PHP opcode caching is enabled to avoid recompilation on each request.
Database tuning for traffic spikes
Find and fix slow queries
Enable the slow query log and address the real offenders. Start with missing indexes, trimming SELECT *, and avoiding N+1 patterns.
References: MySQL slow query log and MariaDB slow query log.
WordPress hint
Audit autoloaded options and heavy postmeta joins. The Action Scheduler plugin also benefits from cleanup and proper indexing.
Right-size InnoDB and connections
Size the buffer pool, log files, and max connections to fit your real workload. Match PHP-FPM workers to prevent DB exhaustion.
Offload reads and heavy tasks
Use a read replica for reporting and offload search or media to dedicated services. Serve files through a CDN.
Queues that smooth traffic surges
Queues turn spikes into lines. Anything that does not need to block the user should be queued: emails, webhooks, CRM syncs, image optimization, exports, and sitemap builds.
WordPress specific
Disable pseudo cron and run real cron every minute. If you rely on Action Scheduler, increase concurrent runners, keep jobs idempotent, and prune logs weekly.
Load testing that reflects real behavior
Test with the CDN on. Mix anonymous and logged-in users. Include add to cart, checkout, search, and API calls. Shoot for at least 1.2 to 1.5 times expected peak. Record p95 latency, error rate, CPU, DB connections, and queue depth. Fix, retest, and repeat.
Operational guardrails while preparing a site for traffic spikes
Make one change at a time with a clear rollback. Rate-limit abusive IPs and paths at the edge. Use feature flags for risky features. Keep a single decision channel with an incident lead.
Quick checklist
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Edge cache configured with proper bypass rules
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Page cache enabled and prewarmed
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Redis object cache with high hit ratio
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Slow query log reviewed and fixed
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InnoDB and PHP-FPM sized from measurements
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Noncritical work queued with monitored workers
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Load test complete with target concurrency
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On-call plan and rollback steps ready
How Sentree fits in
Sentree bakes these safeguards into your stack. We tune caching at the edge and the app, deploy Redis, analyze slow queries, right-size PHP-FPM and the database, and set up queues with monitored workers. Before your event we run load tests, prewarm caches, and staff an on-call window. During and after the spike, we watch the same metrics you care about and act fast when something drifts.
By following this plan, you will be preparing a site for traffic spikes with confidence and keep conversions flowing when attention is at its highest.
Ready to prepare your site for its biggest day? Tell us the date and your expected traffic. We will run a quick assessment and give you a step by step plan.
Questions? Email us at marketing@sentree.io.
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