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Latency seen on Windows client on SQL Index Rebuild for a DB on 16 LUNs from CVO-HA

Last Updated:

Applies to

  • Microsoft  Structured Query Language (MS SQL) Index Rebuild
  • SQL Database (DB) ISCSI LUNs on CVO
  • read latency on Client side
  • Microsoft Azure
  • Cloud Volumes ONTAP High Availability (CVO HA)
  • Active-Passive LUN distribution on CVO
  • Windows client and Azure CVO in same vNET and no firewall
  • CVO HA NICs for ISCSI fine


  • ISCSI read latency upto 15 to 20ms seen on Windows client on SQL Index Rebuild for a DB spread on 16 LUNs from CVO-HA.
  • LUNs are configured one each per volume and all volumes located on one node on CVO-HA in active passive configuration.
  • CVO side latency measured from disks to network layers shows average of 5ms.
  • Packet traces between windows client and Azure CVO HA showed packet drops and old congestion control in play.

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