How do I know, if my DC have 100 000 or 500 000 of capacity?
In the CAPC GUI, under Administration -> Monitored Items Management -> Data Collectors you can select a Data Collector and click the Capacity button to set the capacity that you would like to display. All this setting does it to give the Capacity Utilized column a number to go off of to display Capacity %.
Yes. But my question is, how do I know that my DC is able to handle 100000 or 500000 items?
What are the recommended specs that I should have on my VM for that values.
I have the online tool that we have on CA docs, but, on that tool the DC specs do not only depend on the number of items...
Technically speaking, you can choose whichever you want. The only thing it effects is the utilization column. Ideally, you should size your environment using the below sizing wizard to know if you can feasibly have 500k items based on the specs of your DC.