Strange Supplemental Storage behavior in VCF 4.5

[vTristanTodd]

New VCF environment running support all-flash fC-connected SAN. With no production workloads yet, we see no IO at all.

Just upgraded to VCF 4.5 and suddenly we are seeing cyclical Read IO from the VCF hosts (peak of about 150 MBps per host) with no running VMs. We did a test where we put the half of the hosts in maintenance mode and removed from SDDC manager. 

Hosts go into maintenance mode, no change in read IO

Hosts removed from SDDC manager, read IO drops to nothing

This behavior was not observed in VCF 4.5.

Any ideas on what might be going on?

Thanks in advance!

[vTristanTodd]

We my have found the underlying issue...

With VCF 4.5, there is also the upgrade of NSX manager from 3.1.x to 3.2.x. The new plugin that came with NSX mgr 3.2.0 has a known issue that is covered here - https://kb.vmware.com/s/article/89461. If anyone else is seeing odd IO after VCF upgrade, maybe this applies...