News

Microsoft Releases Exchange Server 2013 CU2

• By Kurt Mackie
• 07/10/2013

Microsoft on Tuesday released Cumulative Update 2 (CU2) for Exchange Server 2013.

The CU2 release (Build 15.0.712.22) is right on time in accordance with Microsoft's new update release cycle for Exchange 2013. Those releases now occur on a quarterly basis. Microsoft released CU1 for Exchange 2013 back in April, and explained its new cumulative update policy earlier this year. Essentially, Cumulative Updates are full server releases now. They get delivered every three months via the Microsoft Download Center and arrive as fatter files now since they are full server installations.

New in CU2
A big part of this CU2 release was supposed to be its expanded support for 100 databases per server, instead of 50 databases per server, for the Enterprise edition of Exchange 2013. Microsoft had played up this expansion last month, signaling that it was making the change in reaction to customer complaints about the limitation. However, customers may just be getting an expanded capacity in name only, according to the announcement of CU2 by Ross Smith IV, principal program manager for the Exchange customer experience.

"As mentioned previously, Exchange 2013 RTM CU2 increases the per-server database support from 50 databases to 100 databases in the Enterprise Edition of the product," Smith wrote. "Please note that this architectural change may not provide any additional scalability as CPU may be a bottleneck, thereby limiting the number of mailboxes you can deploy per-server."

Smith didn't explain what IT pros could expect from the capacity changes made in CU2, but he did point those deploying CU2 to a new release of the Exchange 2013 Server Role Requirements Calculator, which was updated today.

In addition to the theoretical expansion of the number of databases per server, Microsoft added a few more perks in this CU2 release. The update enables a single sign-on capacity for the Outlook Web App when using forms-based authentication. Search within the Outlook Web App has been improved as well. A new database availability group (DAG) management service was added in CU2 for tracking failovers and ensuring high availability. Throttling per group was introduced in CU2, instead of per server, which allows the restart service to "execute every 60 minutes DAG-wide," according to Smith. IT pros also now can update their Exchange management shell's PowerShell cmdlets via an update process within the shell itself after the CU2 release is installed.

Test Then Deploy
Microsoft recommends deploying these cumulative updates after testing them as soon as they become available, according to Smith. He suggested that organizations should deploy the cumulative updates particularly if they have hybrid deployments -- that is, computing environments that tap both Microsoft's Office 365 public cloud services and Exchange Server 2013 on-premises installations. Using these cumulative updates better ensures that the cloud and server deployments both run the same code, he explained.

Service packs will still get released for those organizations that can't keep up with Microsoft's new quarterly cumulative update release cycle for Exchange Server 2013.

"We realize that some customers spend several months validating environments, third-party products, etc., and require more time for testing," Smith wrote in the announcement. "Therefore, we will continue to ship a Service Pack which provides all of the updates included in prior cumulative updates in one installation and acts as a logical milestone for updating your servers."

IT pros that deploy the cumulative updates are still on the hook to test them, and Microsoft offers plenty of warnings associated with CU2. For instance, organizations with older versions of Exchange shouldn't obliterate them when installing Exchange 2013, unless they no longer want to see that legacy version in their computing environment again. Removing the last server role of a legacy version of Exchange will make it no longer possible to reintroduce that version again after Exchange 2013 is installed, according to Smith.

CU2 contains both schema changes and Active Directory changes. A couple of setup commands need to be executed to prepare both prior to the CU2 installation, according to Smith.

In addition to installation caveats, there are uninstall caveats. Exchange 2013 has a different architecture compared with earlier releases. It has just two server roles, a mailbox role and client role. There's a restriction on uninstalling the two roles if they are both installed on a single machine. Users have to remove both of them at the same time in that case. It's not possible to uninstall them individually. Moreover, in order to manage Exchange 2013, both roles must be installed.

Microsoft also made mailbox size reporting more accurate in Exchange 2013. Consequently, organizations migrating mailboxes from older Exchange Server versions to Exchange 2013 will see their mailbox sizes increasing by about 30 percent, on average, according to Smith. That means that IT pros may have to bump up individual mailbox quota limits before migrating mailboxes to Exchange 2013 so as not to lock out end users.