Extreme Latency Spikes in ESXi 6.5, but not in ESXi 5.5

Hello everbody,

we have two different vSphere environments - both are running on Cisco UCS and Hitachi HDS Storage.

One environment has new hosts with the Cisco ESXi 6.5 U1 ISO, VSCA 6.5.

The second environment is running with ESXi 5.5 U3 Hosts, VSCA 6.5.

Now we have many latency alerts from the first environment with read latency up to 7 minutes. But there is no impact within the guest os or other VMs running on this host or datastore.

We see this latencies in veeam and in the vcenter.