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When do ONTAP metrics measure round trip time to clients or only internal ONTAP time?

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ontap-9
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perf
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Applies to

  • ONTAP 9
  • ONTAP S3 Server
  • FCP
  • iSCSI
  • CIFS
  • NFS

Answer

NAS
  • NAS protocols (CIFS/NFS) only measure the time the CIFS/SMB/NFS request packet was ingested to the Network layer, processed, and response completed at Network layer.
    • There is some time not covered between the Network layer and the packet being sent on the wire, but this is minimal.
    • If viewing in Wireshark, you will see the NFS/SMB response time (Service Response Time, or SRT) after the request.
  • Each protocol does split a large read or write into chunks, but the network time is not tracked for this.
SAN
ONTAP S3 Server
  • The S3 protocol is similar because it can be many megabytes per request, so the TCP delay between request and final completion can be tracked in the Network delay center.
  • Large reads or writes (GETs/PUTs) may be split up into chunks, and this is tracked.
  • This graphic shows some of the delays possible in the Network column of qos statistics volume latency show

S3 network delay.png

Additional Information

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