Why has Edgio's CDN service seen a 15% drop in cache hit ratio over the past week?

Introduction

The recent 15% drop in Edgio's CDN service cache hit ratio is a critical issue that demands immediate attention. As we analyze this product performance decline, we'll follow a systematic approach to identify, validate, and address the root cause while considering both short-term fixes and long-term strategic implications.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking there might have been a recent change in content or traffic patterns. Has there been any significant shift in the type or volume of content being served through the CDN in the past week?

Why it matters: Changes in content type or volume can directly impact cache hit ratios. Expected answer: There may have been an increase in dynamic content or a new large customer onboarded. Impact on approach: If confirmed, we'd focus on content optimization strategies or customer-specific caching rules.

• Considering the scale of the drop, I'm wondering about system-wide changes. Have there been any recent updates to the CDN infrastructure or caching algorithms?

Why it matters: System changes could inadvertently affect caching behavior. Expected answer: A recent update to the caching algorithm or infrastructure changes might have occurred. Impact on approach: If true, we'd prioritize reviewing and potentially rolling back recent changes.

• Given the specificity of the 15% drop, I'm curious about the measurement consistency. Has there been any change in how we measure or calculate the cache hit ratio?

Why it matters: Ensures we're dealing with a real performance issue, not a measurement anomaly. Expected answer: No changes in measurement methodology. Impact on approach: If there were changes, we'd need to reassess the actual performance impact.

• Thinking about external factors, I'm considering user behavior changes. Have we observed any shifts in user access patterns or geographic distribution of requests?

Why it matters: User behavior changes can significantly impact caching effectiveness. Expected answer: Possible shifts in traffic patterns or new markets being served. Impact on approach: If confirmed, we'd focus on optimizing caching strategies for new usage patterns.