ISE Sizing on Virtual Machines

The current ISE VM performance/scalability guidelines are based on the ISE appliance configuration (i.e. similar configuration yields similar results). If you have the same VM requirements as the appliance has, it will have the same results. As an example 3315 can support up to 3,000 concurrent endpoints, 3355 can support up to 6,000 concurrent endpoints and 3395 can support up to 10,000 concurrent endpoints.

Below are the documents you need for reference. Installing the Cisco ISE System Software on a VMware Virtual Machine. See. Table 4-1 Minimum VMware System Requirements
http://www.cisco.com/en/US/docs/security/ise/1.0.4/install_guide/ise104_vmware.html
**Update 10/01/2014
http://www.cisco.com/en/US/docs/security/ise/1.2/installation_guide/ise_vmware.html

Introducing the Cisco ISE Hardware. See. Cisco ISE 3300 Series Appliance Hardware Summary
http://www.cisco.com/en/US/docs/security/ise/1.0.4/install_guide/ise104_ovr.html
**Update 10/01/2014
http://www.cisco.com/en/US/docs/security/ise/1.2/installation_guide/ise_ovr.html


So just to recap the maximum number of end points on the virtual appliance is 10,000 but it depends on the amount of resources allocated to that virtual appliance as to what can actually be supported.
If the virtual appliance only has a similar amount of resources as the physical 3315 appliance then it will only handle 3,000. And the same is true for the 3355 etc.

**Updates 10/01/2014
It's worth noting the ISE hardware has recently been updated, the appliances are now the SNS 3400 series and below is a link to the hardware specification: