Exchange 2013 CU2 Coming Summer with Restored 100-Database Support

Microsoft announced that it will release Cumulative Update 2 (CU2) for Exchange Server 2013 sometime this summer.

For the Enterprise edition, the update will increase the maximum number of supported databases per server from the current 50 to 100, according to a post on the Exchange blog by Ross Smith IV, principal program manager for Microsoft's Exchange Customer Experience team.

In developing Exchange 2013, Microsoft initially lowered the limit for supported databases from 100 to 50 to improve performance. The company is restoring the original 100-database limit with CU2 in response to user complaints, Smith said.

"Since the release of Exchange 2013, we've received an inordinate amount of feedback regarding the reduction in supported databases per-server. The driving response has been 'we currently deploy more than 50 databases per-server in Exchange 2010; with this change, this means we will need to deploy more servers, which increases our capital expenditures significantly,'" he wrote. "Rest assured, that is not the message we want with Exchange 2013. It is true that Exchange 2013 utilizes more CPU and memory than its predecessors -- this is due to the architecture changes we've made, as well as the changes we've made to reduce disk IO, so that you can deploy more mailboxes per disk. But we do not want to see architectures artificially limited by the supported databases per-server constraint.

Smith explained the reasoning behind cutting the number of supported databases in the first place. He said that Microsoft initially thought that there was a "lack of real world usage" beyond 50 databases per server, but that customers said otherwise.

The new server supports the use of commodity hardware and its new architecture made the product more CPU- and memory-reliant than Exchange 2010, Smith explained. Microsoft replaced the old content indexing service with Search Foundation and rewrote the store.exe process. Those architectural changes and a few more were somehow associated with the 50-database limitation, perhaps, per Smith's explanation, although it's not exactly clear why.

CU2 will become available "later this summer," Smith said. Microsoft released CU1 of Exchange 2013 in April. Earlier this year, Microsoft announced it would adopt a quarterly release schedule for Exchange 2013 cumulative updates, which are different from update rollups (RUs). Cumulative updates, as their name suggests, contain all past updates and hotfixes, including past update rollups. On the other hand, update rollups are sequential, meaning an RU2 of one product will not contain security fixes from RU1.