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ONTAP SAN Protocol Latency VMware Connected via Blade Chassis Interconnects

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ontap-9
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san
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Applies to

  • NetApp AFF
  • ONTAP 9
  • VMware ESXi 7.0 Update 3g
  • HPE Blade Chassis with Ethernet/FCoE interconnects
  • Brocade Fibre Channel Switches

Issue

  • VMware hosts and applications experienced high protocol latency, despite low storage volume latency on the NetApp storage.
  • Latency spikes were observed in both VMware and ONTAP protocol metrics, particularly affecting production VMs (e.g., Kafka cluster).Latency values exceeded 100ms, with peaks up to > 200ms .
  • esxtop we continue to see high DAVG values to collect esxtop batch data at time of issue
Example log output:
WARNING:ScsiDeviceIO:1513:Device naa.600a0980383 performance has deteriorated. I/O latency increased from average value of 20762 microseconds to 419996 microseconds
esxtop   
  DEVICE        DQLEN WQLEN ACTV QUED %USD  LOAD   CMDS/s  READS/s WRITES/s MBREAD/s MBWRTN/s DAVG/cmd KAVG/cmd GAVG/cmd QAVG/cmd
naa.600a0980383    64     -   53    0    0  0.00   256.66    62.58   194.07     2.11    92.62    99.21    15.48   114.69    15.47
naa.600a0980383    64     -   49    0    0  0.00   179.29    41.60   137.69     3.60    61.30   186.69    87.77   274.46    87.75
naa.600a0980383    64     -   64  108    0  0.00     1.48     0.20     1.29     0.01     0.62   226.75   266.06   492.81   266.04

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