Q. Is it possible to mix server types in a Cisco Unified Communications Manager Cluster?
A. A single Cisco Unified Communications Manager Cluster can contain different Server types under the following guidelines:
THESE GUIDELINES APPLY FOR BOTH PHYSICAL AND VIRTUAL SERVERS, THE ONLY RESTRICTION IS THAT SINCE CUCM 10.X YOU CAN ONLY HAVE VIRTUAL SERVERS.
* Supporting servers, Publisher and TFTP, must be equal to or better than all other servers in the cluster. i.e. if your cluster contains subscribers that are 7845s, (or using a 10,000 users OVA), then the publisher and TFTP must be 7845s / use the same OVA.
* Care must be taken so that in failover situations, you will not oversubscribe a single server. i.e. you can't have a 7835 back up a 7845, (or a 2,500 users OVA to backup a 7,500 users OVA)
* It is recommended that you deploy pairs of like servers. i.e. a 7835 backs up a 7835, a 7845 backs up a 7845, same for OVAs, use the same type.
* 7815/16 servers cannot be part of a cluster with higher servers.
- MCS 7815 and MCS 7816 servers support only 1+1 redundancy (maximum of 2 servers) and cannot be a member of a cluster containing other servers.
- The MCS 7816 server supports a maximum of 500 users.
- The MCS 7815 server supports a maximum of 300 users.
- When deploying a cluster with Cisco MCS 7816 or equivalent servers, there is a maximum limit of two servers in a cluster: one as the publisher, TFTP server, and backup call processing server, and the other as the primary call processing server. A maximum of 500 phones is supported in this configuration on a Cisco MCS 7816 or equivalent server.
This is similar to some BE 6K restrictions, some virtual servers will only support having a single SUB, so you can only build clusters of 2 servers, check the documentation of the specific product you are planning to install, so there are no surprises later.
* When deploying a two-server cluster with higher-capacity servers, Cisco recommends that you do not exceed 1250 users in the cluster. Above 1250 users, a dedicated publisher and separate servers for primary and secondary call processing services is recommended, thus increasing the number of servers in a cluster.
* Server types from different manufacturers (ie. HP and IBM) can be used as long as the guidelines above are followed.
* You CAN mix Virtual and Hard servers in a CUCM cluster up to 9.x, CUCM 10.x no longer supports bare metal servers.
* You CAN mix Virtual and Hard servers in a cluster as long as the guidelines above are followed. (CUCM 8.0+ only)
* You CAN mix Virtual and Hard servers when clustering over the WAN if you follow the 'clustering over the WAN' guidelines that are on the CUCM SRND
* If you will be using UCS servers, you must follow the rules and guidelines on the docwiki for UCS and 3rd party servers for UC-on-UCS.
* When using CUCMBE 6000 (CUCM 8.5+ only) you can use a secondary UCS C200 UCS C200 Rack-Mount Server (or MCS server) to provide high availability for call processing as well as other applications and services.