Cisco ISE software has to be in synchronization with the chip and appliance capacity to support latest CPU/Memory capacity
available in the UCS Hardware. As ISE version progresses, support for older hardware will be phased out and newer hardware
is introduced. It is a good practice to upgrade Virtual Machine (VM) capacity for better performance. When planning VM upgrades,
we highly recommend to use OVA files to install ISE software. Each OVA file is a package that contains files used to describe
the VM and reserves the required hardware resources on the appliance for Cisco ISE Software Installation.
For more information about the VM and hardware requirements, see the "Hardware and Virtual Appliance Requirements" in Cisco Identity Services Engine Installation Guide
Cisco ISE VMs need dedicated resources in the VM infrastructure. ISE needs adequate amount of CPU cores akin to hardware appliance
for performance and scale. Resource sharing is found to impact performance with high CPU, delays in user authentications,
registrations, delay and drops in logs, reporting, dashboard responsiveness, etc. This directly impacts the end-user and admin
user experience in your enterprise.
 Note |
It is important that you use reserved resources for CPU, memory and hard disk space during the upgrade instead of shared resources.
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If you are upgrading from VM based out of 33x5 appliance, then the upgraded VM need to use more CPU core( OVA for 3515 allocated
approximately 6 Core and OVA for 3595 uses 8 Core/64GB RAM with HT enabled). Check out the OVA requirements for ISE 2.4 for
more details.
34xx series appliances are not supported in Cisco ISE, Release 2.4 and later.
Cisco ISE, Release 2.4 and later requires a minimum disk size of 300GB for virtual machines as the local disk allocation is
increased to 29GB.