What caused the unexpected 25% spike in VMware's vSAN storage latency for our enterprise customers last week?

Introduction

The unexpected 25% spike in VMware's vSAN storage latency for enterprise customers last week is a critical issue that demands immediate attention and thorough analysis. As we delve into this problem, 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 this could be related to a recent update. Has there been any software or firmware updates to vSAN or related components in the past two weeks?

Why it matters: Recent changes are often the culprit in sudden performance issues. Expected answer: Yes, there was a minor update. Impact on approach: If yes, we'd focus on the update's contents and rollout process.

• Considering the scale, I'm wondering about the affected customer base. Is this latency spike uniform across all enterprise customers or concentrated in specific segments?

Why it matters: Helps determine if it's a global issue or specific to certain deployments. Expected answer: It's affecting 80% of enterprise customers. Impact on approach: If concentrated, we'd investigate common factors among affected customers.

• Given the nature of vSAN, I'm curious about any changes in data patterns. Have there been any significant changes in data volume or type being processed recently?

Why it matters: Unusual data patterns could strain the system unexpectedly. Expected answer: No significant changes noted. Impact on approach: If yes, we'd examine data handling processes and capacity planning.

• Thinking about external factors, has there been any change in network infrastructure or cloud provider services that vSAN interacts with?

Why it matters: External dependencies could be causing bottlenecks. Expected answer: No major changes reported. Impact on approach: If yes, we'd coordinate with network teams and service providers for further investigation.