CUCM Sizing Question

[gmckay948bt]

Is it possible to state categorically how many users a cluster with a MCS-7835I3-K9-IPC1 publisher and single MCS-7835I3-K9-IPC1 subscriber can support on CUCM 8.x?

Regards

[Stephane Cohen]

Hello Gordon

Trouble with this configuration is you need to plan for worst case scenario where you lose the SUB and PUB runs all services.

See  Cisco Unified Communications System 8.x SRND

http://www.cisco.com/en/US/partner/docs/voice_ip_comm/cucm/srnd/8x/callpros.html#wp1159144

When deploying a two-server cluster with high-capacity servers, Cisco recommends that you do not exceed 1250 users in the cluster. Above 1250 users, Cisco recommends a dedicated publisher and separate servers for primary and backup call processing subscribers.

Regards,

Stephane

[troullier00]

The maximum users is shown in this chart taken from the CUCM 8.x SRND. Besides the users I would really prefer to look at the call capacity with a erlang calculation. Having 1000 phones in a call center is very different than having 1000 phones in an office with average call volume.

The maximum number of users Unified CM can support depends on the server platform, as indicated in Table 8-3.

Table 8-3     Maximum Number of Endpoints per Server Platform

Server Platform Characteristics	Maximum Endpoints per Server1	High-Availability Server2
Cisco UCS C210 Rack-Mount Server	7,500	Yes
Cisco UCS B200 Blade Server	7,500	Yes
Cisco MCS 7845 (All supported models)	7,500	Yes
Cisco MCS 7835 (All supported models)	2,500	Yes
Cisco UCS C200 Rack-Mount Server	1,000	Yes
Cisco MCS 7825 (All supported models)	1,000	No
Cisco MCS 7816 (All supported models)3	500	No
Cisco MCS 7815 (All supported models)3	300	No

¹ A  platform that is not a high-availability server can support a maximum  of 500 endpoints in a non-redundant single server installation.  High-availability servers can support a maximum of 1000 endpoints in a  non-redundant single server installation.

² A high-availability server supports redundancy for both the power supplies and the hard disks.

³ 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.