no, there are no PVSCSI errors in my VSA vmware.log.
This latency issue had been there from the first start. Tried it with 9.5, upgrade to 10.0, fresh installation of 10.5.
HP assigned the case to some 3rd level engineers, they collected loads of logs, but nothing came out of it.
We agreed then that the 1gb uplink might be the bottleneck. But last week we upgraded everything to 10 gb - but the performance didn't improve at all.
I noticed one thing: If we use just one node (and the FOM), then performance is very good. If the second node is up again, then latency rises to more than 500 ms.