_Event.Heartbeat stops when remote UI connects

[NikolayLevchenko]

We have a redundant pair of servers and we use _Event.Heartbeat and _Event_2.Heartbeat datapoint elements for some monitoring purposes.

We noticed a strange behaviour of these DPE's. When a new remote UI (gedi) is started and connects:
On Server A DPE _Event_2.Heartbeat stops updating for several seconds, then jumps up very quickly, then stops again for a few seconds and then starts
On Server B the same happens on DPE _Event.Heartbeat

We checked Windows Process Monitor and we can't see any increased load on CPU or network.

It is as if servers stop getting values from each other. This seems strange. Any explanations/advice, please?

[leoknipp]

Probably the hostname/IP-address resolution does not work and therefore the heartbeat stops.
Have you defined the hostname and IP-address of the clients in the hosts file of the servers?

If not please make the entries and check afterwards if the problem is solved.

Best Regards
Leopold Knipp
Senior Support Specialist

[NikolayLevchenko]

Hi Leopold, thanks for the response.

The problem is not really on the client, I use a PARA GUI on the servers themselves to watch the Heartbeat DPEs. Also, the control managers that run on servers have debug statements that tell me that they stop receiving values from the Heartbeat DPEs.

[leoknipp]

If a connection is established the server processes (Data-/Event-Manager) try to resolve the hostname/IP-address. The process has to wait for the response of the operating system call and therefore the server process is "blocking".
Please check the settings in the hosts file.

Best Regards
Leopold Knipp
Senior Support Specialist

[NikolayLevchenko]

I've checked "hosts" file on both servers and they both have each other in the "hosts" file like:

xxx.xxx.xxx.1 server_A server_A-1
yyy.yyy.yyy.1 server_A-2

xxx.xxx.xxx.2 server_B server_B-1
yyy.yyy.yyy.2 server_B-2

[leoknipp]

The hostname and IP-address of the client where the user interface is started must be defined in the hosts file.
Another possible solution is to use the config entry noReverseLookup = 1 at the servers.

Can you please check if it works when the entries or the config entry is defined.

Best Regards
Leopold Knipp
Senior Support Specialist

[NikolayLevchenko]

Thanks, Leopold. This seems to have fixed it. Now my remote UI starts a lot quicker, actually, and the heartbeats do not seem to stop.