Clarification on ArcSOCs.

Yogesh_Chavan

Hi,

I wanted to understand how ArcGIS Server ArcSOC's distribution works across multiple machines.

We have HA 11.4 Enterprise deployment, with ArcGIS Server on 2 machines(Site + Joined Site). What I am trying to understand is how does ArcSOC instances gets distributed across the two server machines.

For example: We have a machine critical geocoding service with min and max instances both set to 40.

So the query I have is:

If we have set Minimum Instances set to 40, we observe 20 instances on machine A and 20 instances on machine B. So, is this a correct observation? How is ArcSOCs designed to be distributed? 20 Per machine(Total 40 for 2 machines) or 40 Per machine(Total 80 for 2 machines)?

https://enterprise.arcgis.com/en/server/11.5/deploy/windows/anticipating-and-accommodating-users.htm?utm_source=chatgpt.com#:~:text=Adjust%20dedicated%20instance,in%20traffic%20volume.

Thanks!

 

Priya_Das

Hi @Yogesh_Chavan 

In an ArcGIS Server multi-machine site, each machine runs its own pool of ArcSOC processes for each service. The minimum number of instances and maximum number of instances you configure for a service apply per machine, not across the entire site.

1. Plan per machine capacity — The service settings should consider RAM and CPU availability per server.
2. Multiply by number of machines — Total ArcSOC count = per machine × number of machines.
3. Monitor ArcSOC usage — Use ArcGIS Server Administrator Directory (/admin) or logs to see actual usage.
4. Avoid excessive min instances — High min values can consume memory even if idle.

If you’re observing 20 on each machine instead of the full 40:

• The service may not actually be honoring the configured minimum due to:
  • Publishing or config not updated — the service might have been restarted with a lower min setting.
  • Machine resource limits — ArcGIS Server may reduce the number of prestarted instances if there is insufficient memory or CPU.
  • Observation method — If you’re checking via Task Manager or ArcGIS Server logs, you might be seeing only active instances, not idle prestarted ones.
  • Shared instances — If the service is configured to use the shared instance pool (available for map services), the min/max instance settings don’t apply in the same way.