Why has WEKA's WekaFS file system performance declined by 15% for read operations over the past month?

Introduction

The recent 15% decline in WekaFS file system performance for read operations is a critical issue that demands immediate attention. As we delve into this problem, we'll employ 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)

• I'm noticing the specific mention of read operations. Would you say this decline is isolated to read operations, or are write operations affected as well?

Why it matters: This helps us narrow down the scope of the issue and potential causes. Expected answer: Only read operations are affected. Impact on approach: If only reads are affected, we'll focus on components specific to read operations.

• Given the 15% decline, I'm wondering about the baseline. What was the typical read performance before this decline?

Why it matters: Understanding the baseline helps quantify the impact and set restoration targets. Expected answer: A specific throughput or IOPS number for normal operations. Impact on approach: This will help us set clear goals for performance recovery.

• Considering the one-month timeframe, have there been any significant system changes or updates during this period?

Why it matters: Recent changes often correlate with performance issues. Expected answer: Information about recent updates, patches, or configuration changes. Impact on approach: If changes occurred, we'll prioritize investigating their impact.

• I'm curious about the workload patterns. Has there been any shift in the types of files being accessed or the access patterns over the past month?

Why it matters: Changes in workload can significantly impact file system performance. Expected answer: Information about any changes in file types, sizes, or access patterns. Impact on approach: This will guide our investigation into potential workload-related causes.