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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

Do you have a performance issue?

·      Performance is about expectations

o   Knowing if you have a problem requires understanding your expectations

·      Expectations can be implicit or explicit

o   Implicit expectations – AFF platforms should see latency < 2ms (on average)

o   Explicit expectations – MS Exchange requires latency to average < 20ms

·      Are users filing tickets/reporting issues?

o   Users filing support tickets or raising concerns about performance for the storage environment

o   Are applications generating alarms regarding performance?

o   Are jobs failing or taking longer than expected?

Is it due to CPU?

·      Using ActiveIQ Unified Manager, drill down into the Volume Performance

o   Looking at the Cluster Components the two main CPU resources are

§  Network Processing

§  Data Processing

o   If these two components make up the majority of your latency, then CPU is the primary factor in overall latency.

§  Note that simply having latency coming from CPU is normal.  In most AFF systems, CPU is going to be the primary contributor to latency.  Only if the latency seen is higher than expected would it be a “problem”.

·      Using CLI to collect QoS statistics from a cluster in real-time

o   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

o   As with UM, if these two components comprise the majority of latency, then CPU is the primary factor in overall latency