Cucm 12.5 Virtualization Requirements __hot__ - Cisco

Always match the exact RAM from Cisco’s OVA template. Adding more RAM than specified can actually break memory addressing in the real-time kernel.

Do not over-allocate vCPUs. Adding more vCPUs than the OVA spec increases context-switching overhead, degrading performance.

Q: What VMware vSphere version is supported by CUCM 12.5? A: CUCM 12.5 supports VMware vSphere 6.7, 6.5, and 6.0. cisco cucm 12.5 virtualization requirements

Voice systems are storage-sensitive. High I/O latency (above 20ms) will cause call control and voicemail failures. CUCM 12.5 has abolished spinning disks for production.

To ensure success:

Database replication fails within hours. Fix: Re-deploy on RAID 10 LUN.

For the most current and specific information, always consult the official document: "Cisco Unified Communications Virtualization Requirements" (OL-28717-01) for CUCM 12.5(1). Always match the exact RAM from Cisco’s OVA template

| Hypervisor | Minimum Supported Version | Key Notes | | :--- | :--- | :--- | | | 6.7, 7.0, 8.0 | The only fully supported hypervisor for production. | | Cisco HyperFlex | 3.0, 4.0 | Supported when using ESXi as the underlying hypervisor. | | Nutanix AHV | Limited support | Only for specific partner-managed solutions; not general purpose. | | Microsoft Hyper-V | Not supported | Use only for demo/lab, not production. | | KVM / Proxmox | Not supported | No support; TAC will reject. |