ArcGIS Sever 10.9.1: How to determine the number of shared instances?

Question

For example, if the server machine has resources of 4 cores, what is the best value that needs to be allocated as “number of shared instances”?

How about the “number of cached services”?

JamalNUMAN · Answer

Thank you for the input.

My point here is that the two types of pooling (dedicated\shared) need to be available for all types of services, and it’s the choice of the admin where to go

LongDinh · Answer

Hi @JamalNUMAN ,

A map cache is different to the shared pool instances cache.

The map cache is an organised storage structure of images which optimises retrieval of images (e.g. basemap tiles). See notes here

The shared pool instance cache, like any cache, may be storage of the ArcSOC.exe (and related ArcGIS Server processes) so that the service can respond quickly when called.

Read this blog which will explain the concept of shared instances.

Why not having all types of services consuming from all shared instances (cores)?

You can, but for any computing solution, there are always drawbacks which you should aware of them. For shared instances, say you set all your services to use the pool but you have a service that has a demand peak that is significantly larger than all the other services. That demanded service will utilise more from the pool and negatively impact your other services and their ability to response to their requests. In this scenario, the high demand service should have it's own dedicated instances to avoid impacts on the pool.

I am making guesses here, but for the case of ESRI Utility and System tools, these are set to dedicated as they may be requested internally by services on your ArcGIS Server machine and/or as part of ArcGIS Pro/ArcMap - a requirement by the software.

JamalNUMAN · Answer

I couldn’t figure out why the number of cached map services need to be set in 10.9.1? Why not having all types of services consuming from all shared instances (cores)?

This is in addition to the fact that system and utilities services can’t be set as shared!