Seeking quality with Exchange 2013 CU3

Just in time for Thanksgiving, Microsoft has released Exchange 2013 CU3 (build 15.0.0775.38), some four months since the release of Exchange 2013 CU2. It’s time for administrators to swing into the process of figuring out how to introduce the new software into production environments, making sure to test CU3 thoroughly against the unique features of those environments, including the interaction with third-party products. The new update is available now from the Microsoft Download Center. 

On November 20, Microsoft announced that Exchange 2013 Service Pack 1 (really CU4 under another name) is coming "early next year". Let's see: November 25 + 13 weeks means that we should mark the end of February 2014 in our diaries, right?

To complete the flurry of update activity, Microsoft also released Roll-up Update 3 (RU3) for Exchange 2010 SP3. 

To revert to CU3, Microsoft has run through choppy waters with the new servicing model for Exchange 2013, which requires customers to install the latest available update to receive support for problems that they encounter. CU1 (April 2) made a good impression because it fixed many of the problems experienced with the RTM software and laid the foundation for co-existence with Exchange 2010 and Exchange 2007 servers. The CU2 (July 9) release was affected by a problems introduced by security patch MS13-061. Microsoft aims to release cumulative updates on roughly a quarterly basis, but in line with their commitment made after the MS13-061 problems, Microsoft delayed CU3 to ensure that no quality issues exist in the software. So far, the signs are good and I have only seen good results in running beta versions successfully for the last month or so.

As with any new software release, people are interested to know what new features have been added. The answer is “not much in reality” and bug fixes such as the one that a fixes a problem in restoring backup datasets are much more of a focus in CU3 than the new introduction of new features. You can find the full set of fixes included in CU3 in KB2892464 (for a different perspective, read my notes about the individual fixes in CU3). The reduction in the memory taken up by the "noderunner" processes used by the Search Foundation to maintain the content indexes for mailbox databases is also welcome. Despite the relative lack of new features, CU3 still requires an Active Directory schema update.

I consider CU3 to be a stabilization and fit-and-finish release that gets Exchange 2013 to a very solid level of reliability and robustness. Microsoft is correct to take this approach as a solid release will restore some of the ebbing faith in Microsoft QA processes resulting from problems with Exchange 2010 rollup updates and Exchange 2013 CU2.

One feature that is worth mentioning for large organizations is the addition of an “Advanced Search” option to the picker provided by the Exchange Administration Center (EAC) to add members to distribution groups. The old picker works, but it is tiresome to use when you need to build large groups from a large GAL when you have to scroll through the GAL to locate mailboxes and other objects to add to the group. In fact, it’s a great example of a feature that works ever so well in demo or small-scale environments (and passes every QA test) but functions badly in a large deployment.

The new Advanced Search feature allows you to search the GAL on the basis of Active Directory attributes such as City or Country. The picker then displays the objects that meet the search criteria. If all goes well (you specify good criteria and the attributes are correctly populated in Active Directory), then a much smaller subset of objects is displayed, which makes it much easier to add the desired objects to the group. It’s a small but very welcome update.  And if you don’t like it, remember that you can always use the Get-Mailbox cmdlet (with a suitable filter) to locate a set of objects using EMS and then use the Add-DistributionGroupMember cmdlet to add those objects to a group in a single piped command.  Something like:

Get-Mailbox –Filter {Office –eq ‘Dublin’} | Add-DistributionGroupMember –Identity ‘Dublin Users’

Of course, maintaining individual members of distribution groups can be a real pain, especially in large organizations. I favour using dynamic distribution groups for this reason and recommend their use whenever possible.

Those who eagerly scan upgraded servers for signs of new features might be puzzled by the appearance of a new service called the Microsoft Exchange Migration Workflow service. This service will be used in the future but isn't quite ready now so it is left in a disabled state. It appears in CU3 because Microsoft made a decision late on in the development cycle that the features which use the new service aren't ready for deployment in on-premises environments. Removing the service would have created too high a risk to the overall quality of CU3 so it remains, unused and a little unwanted, at least for now.

Do your servers a favor and apply two important updates to fix problems with the .NET Framework 4.5 when you're upgrading to CU3. Exchange 2013 makes extensive use of the .NET Framework, especially in the new "Managed Store", and any updates that improve performance or memory management are welcome. The first update has been around for a while and makes more efficient use of memory per mounted database. More details can be found in my September 5 post. The second is available in KB2862063 (for Windows 2008 R2) or KB2862064 (for Windows 2012). You have to ask Microsoft Support for both fixes.

All of the previous advice about putting DAG member servers into maintenance mode before applying the upgrade apply. On the other hand, don’t mess with maintenance mode when applying the update to standalone servers. Remember too that cumulative updates have the same unfortunate effect on customizations that installing a full version of Exchange (for a CU is a new full version) and so be prepared to redo any customizations to files such as Web.Config, reintegrate Lync with OWA, and so on. Also be sure to check that external connectivity works as expected before you bring the new software into production.

As mentioned above, the next cumulative update for Exchange 2013 will be Exchange 2013 Service Pack 1. Because cumulative updates are full versions of Exchange in their own right, calling the next update Exchange 2013 SP1 is really just an exercise in positioning and naming. It will please customers who plan their maintenance schedules around annual service packs and it will allow those who are determined to wait for the first service pack of any Microsoft product to begin the deployment process. I also hear that the update after SP1 will be named CU5 to emphasize that each update is, in fact, a fully-fledged version of Exchange that stands on its own merits. The difference between a service pack and a cumulative update is now just a name. No more, no less.

On quite another matter, Microsoft has updated and released new versions of the Exchange protocol documentation set. Now, it might seem as boring as watching paint dry to go through the exciting details of what makes protocols like ActiveSync and Exchange Web Services function, but you'd be surprised at the depth of the knowledge that lies in these documents. They are, after all, the documents that Microsoft provides to third parties who want to write code against Exchange and they are backed up with a separate set of articles aimed at helping developers understand how to begin the task of communicating with Exchange via EAS or consuming information held on an Exchange server.

Sometimes companies like Apple don't seem to read the documents as well as they might and so create problems for EAS from the iOS mail app, but the information is all there. I had to pour over these documents when I acted as an expert witness in a UK court case between Google and Microsoft in 2012 and found the information extremely valuable. Recommended!

On a busy day, my summary (based on running a number of beta releases) is that Exchange 2013 CU3 is the best release yet. It appears to match Microsoft’s stated determination to spend as much time as necessary to test so that a new quality benchmark is set. Of course, flaws have been known to pop up soon after the release of previous updates, so stay tuned and monitor developments in this space while you do your own testing. Just in case.

Follow Tony @12Knocksinna

Update December 10: Security bulletin MS13-105 released for Exchange 2007, 2010, and 2013. Make sure that you apply this update after you upgrade a server to Exchange 2013 CU3.