ArcGIS Server intermittent outage? Can the Stopped server on joined site trigger this?

Question

Hello,

We have an ArcGIS Enterprise 11.4 HA deployment. The server is deployed on 2 machines joined together and recently we've started observing server outages more frequently. We saw the first outage in Dec 2025, and we thought of it as a one time issue, and got fixed by re-starting server service on both the machines. Lately in Jan 2026, we saw outage again, and this time just re-start did not fixed the issue, and we observed that stopping server service on 2nd machine brought back the server, so we kept the server on machine B turned down. We did this mid of this month.

Now, the situation has gone worst, the frequency of outages have increased and we're seeing entire server site going down 2-3 times a day, as an example here is the monitor screenshot:

Analyzing the server logs do not gives any helpful results, but we saw one thing that the running server site on 1st machine continuously tries to establish connection checks with server on machine 2.

Now, what we want to understand is can the server on 2nd machine trigger these types of outages, being joined to machine 1 but turned off? Not 100% sure, but what if during peak load, the web adaptor is trying to send requests to machine 2 those are getting lost, and confusing machine 1 and ultimately bringing down the server site?

Thank you so much for any thoughts on this?

Yogesh_Chavan · Answer

Hi @JakeSkinner, thank you so much for looking into this.

The CPU and RAM is optimum and both gets up-to max 45% during peak traffic.

We do not suspect this to be a resource issue, and we did removed the other machine from the site yesterday and did not happen to see the outage in 24 hours yet.

We shall continue monitoring this, but still clueless as to what is the cause of the outages.

JakeSkinner · Answer

Hi @Yogesh_Chavan how is the CPU and RAM on the ArcGIS Server machines when they eventually stop working?

ArcGIS Server should check if the other machine is up and running if it's joined to the site, but this shouldn't cause the application to crash.  You could completely remove it from the site in ArcGIS Server Manager > Site > Machines and see how ArcGIS Server performs.