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How do I know if CPU is causing a performance issue?

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Category:
ontap-9
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perf
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Applies to

ONTAP 9

Answer

Is High CPU utilization causing a performance issue?
  • Performance is about expectations
    • Knowing if you have a problem requires understanding your expectations
  • Expectations can be implicit or explicit
    • Implicit expectations – AFF platforms should see latency < 2ms (on average)
    • Explicit expectations – MS Exchange requires latency to average < 20ms
  • Are users filing tickets/reporting issues?
    • Users filing support tickets or raising concerns about performance for the storage environment
    • Are applications generating alarms regarding performance?
    • Are jobs failing or taking longer than expected?
Is it due to high CPU utilization?
  • Using ActiveIQ Unified Manager, drill down into the Volume Performance
    • Looking at the Cluster Components, the two main CPU resources are:
      • Network Processing
      • Data Processing
    • If these two components make up the majority of your latency, then CPU is the primary factor in overall latency.
    • Note: Latency coming from CPU is normal. In most AFF systems, CPU is the primary contributor to latency. It would be a 'problem' only if the latency seen is higher than expected.
  • Using CLI to collect QoS statistics from a cluster in real-time
    • This will show you the contributions to a workload’s latency by delay center
      • Network and Data are the two CPU resources in this display
    • As with UM, if these two components comprise the majority of latency, then CPU is the primary factor in overall latency

 

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