What caused the sudden spike in latency for Zscaler Internet Access users in the EMEA region yesterday afternoon?

Introduction

The sudden spike in latency for Zscaler Internet Access users in the EMEA region yesterday afternoon 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 regional specificity, I'm wondering if this is an infrastructure issue. Could you confirm if the latency spike was uniform across all EMEA countries or concentrated in specific areas?

Why it matters: This helps pinpoint whether it's a localized problem or a broader regional issue. Expected answer: Concentrated in Western Europe. Impact on approach: If localized, we'd focus on specific data centers or network routes.

• Considering the timing, I'm curious about any recent deployments. Were there any updates or changes pushed to the EMEA environment in the 24 hours preceding the latency spike?

Why it matters: Recent changes are often culprits in sudden performance issues. Expected answer: A minor security patch was deployed the night before. Impact on approach: If confirmed, we'd scrutinize the patch and its deployment process.

• Thinking about user segments, I'm wondering about the impact distribution. Was the latency spike consistent across all user types, or did it affect specific user groups more severely?

Why it matters: This helps identify if it's a general infrastructure issue or related to specific user configurations. Expected answer: Enterprise users were more affected than SMB users. Impact on approach: We'd investigate enterprise-specific configurations or traffic patterns.

• Considering potential external factors, I'm curious about any significant events in the region. Were there any major internet outages or routing issues reported by ISPs in EMEA during this time?

Why it matters: External network issues can sometimes manifest as product performance problems. Expected answer: No major ISP issues reported. Impact on approach: If confirmed, we'd focus more on internal factors rather than external network problems.