This guide covers the essential technical aspects, requirements, and best practices for virtualizing CUCM 15.
Requirements have increased to a minimum of 10GB for small VMs (up from 6-8GB in previous versions). For medium deployments, 12GB is the standard. cucm 15 virtualization
Requirements remain largely consistent with version 14, generally requiring at least 2 vCPUs for standard deployments. Deployment Size Small (150–1,000 users) Medium (2,500–7,500 users) Large (10,000 users) (Specifications based on) 3. Upgrade and Migration Considerations This is not a suggestion
The deep implication here is the elimination of overcommit. In traditional IT, virtualization’s economic benefit comes from oversubscription of CPU and RAM. CUCM 15 explicitly forbids this for production nodes. For a 10,000-user subscriber node, the SSM might mandate 8 vCPUs with 8,000 MHz of reservation and 32 GB of reserved RAM. This is not a suggestion; it is a support boundary. Cisco’s real-time kernel (based on the Precision Time Protocol – PTP) requires deterministic scheduling. If a hypervisor scheduler preempts a CUCM vCPU to service a print server or a development VM, call setup latency spikes, media resources glitch, and CDR logs become corrupted. call setup latency spikes