A question reached me asking what the relationship was between Network Load Balancing (NLB) and Exchange 2010 CAS Arrays and if CAS Arrays superseded NLB configuration of CAS servers.

To answer this question, first you have to know that the difference between CAS servers in Exchange 2007 and Exchange 2010 is that Exchange 2007 CAS servers only process IMAP, POP, Web and Web Services. With Exchange 2010, CAS servers will also handle MAPI traffic. So, besides balancing ports 80, 443 etc. you also need to balance ports 135 (TCP) and 6005-65535 (TCP/UDP) for MAPI RPC ports. Note that you can also use static ports when required, consult kb270836 (it’s an old article, but still valid).

Now on to the new CAS array. CAS array are built on top of load balanced configurations – being hard- or software based. Since the role of CAS servers is becoming more important because it handles all client traffic, it is important to create redundancy at this level. Here’s when Exchange 2010’s CAS array comes into play. With CAS arrays you can create one “virtual CAS server” where you can point all mailbox servers.

The process of creating a CAS array is as follows:

1. Install CAS servers;
2. Set up load balancing, either using NLB or hardware. Don’t forget to add the MAPI RPC ports (see above);
3. Create a DNS record (A) for the virtual IP address of the CAS array, e.g. myarray.contoso.com;
4. Create the CAS array object using the New-ClientAccessArray cmdlet, e.g.New-ClientAccessArray –Name “My Array” –Fqdn “myarray.contoso.com”

Note that there’s a limit of 1 CAS array per site and you can define the site for the CAS array using the Site parameter when required.

(image by Henrik Walter)

The final step depends on the overall installation sequence and if any Mailbox servers existed before the creation of the CAS array, you may need to correct Mailbox servers configuration. These will probably still point to the individual CAS servers, which we can correct using the Set-MailboxDatabase cmdlet like this:

Set-MailboxDatabase Mbx1 -RpcClientAccessServer “myarray.contoso.com”

Note that when a CAS array is present, Mailbox servers will be configured to use that instead of the first CAS server at installation time.

So the answer to the question is CAS Arrays are built on load balanced configurations, load balancing configuration (software or hardware) is still required. For more background information on Client Access Servers in Exchange 2010, consult this TechNet topic.

Microsoft released Rollup 2 for Exchange Server 2007 Service Pack 2 (KB972076). This update raises Exchange 2007 version number to 8.2.234.1.

Here’s the list of changes included in this rollup (kb972076):

1. 961525 Exchange Server 2003 may generate duplicate journal reports in a mixed Exchange Server 2003 and Exchange Server 2007 environment
2. 969230 The “age limits” function of a public folder do not work as expected in an Exchange Server 2007 environment
3. 969948 A Computer that is running Microsoft Exchange Server 2007 that has the Client Access Server (CAS) role installed becomes slow when a user tries to open a folder that contains many items
4. 970817 An appointment is displayed incorrectly as an all-day event if you use a mobile device to synchronize the calendar in Exchange Server 2007
5. 971177 The Auto Attendant ‘Business Hours’ schedule is not updated in Exchange Server 2007 when the DST setting is changed
6. 971349 Exchange Server 2007 users intermittently cannot access an Exchange Server 2003 user’s Free/Busy information in Office Outlook 2007
7. 971889 When Unified Messaging-enabled users call Outlook Voice Access on Exchange Server 2007 to play voice mails messages, there is a delay before the voice mail message is played
8. 972705 The Microsoft Exchange Server 2007 log or database experiences abnormal growth
9. 972744 When a user sends e-mail messages to a remote domain, some e-mail messages are queued on an Exchange Server 2007 Hub Transport server or Edge server
10. 973165 A return address is split into two separate and incomplete addresses when a recipient replies to a specific message in Exchange 2007
11. 973486 Some message parts are not readable when Exchange Server 2007 must convert the message part encoding from binary or from 8 bit to 7 bit
12. 973969 Incorrect exceptions are generated for a recurring iCalendar message when an Exchange Server 2007 server processes an SMTP message that contains the iCalendar message part
13. 974155 OWA does not highlight misspelled words in an Exchange Server 2007 CAS proxy environment
14. 974161 Some attendees cannot receive a meeting cancellation notification when the appointment recurrence pattern is changed by using EWS in Exchange Server 2007
15. 974312 Unread messages are marked as “read” when Exchange Server 2007 processes the EXAMINE command
16. 974344 You still receive an error message when you run the Test-OwaConnectivity command after you apply hotfix KB957485 in Exchange Server 2007
17. 974401 Store sessions are not released when you run the Add-PublicFolderClientPermission cmdlet or the Remove-PublicFolderClientPermission cmdlet in public folders on a computer that is running Exchange Server 2007
18. 974450 A new accepted domain that is added does not work in an Exchange Server 2007 organization
19. 974679 Returned folder names include a question mark when you check the folder names of an Exchange Server 2007 mailbox
20. 974775 The EdgeTransport.exe process crashes intermittently on an Exchange Server 2007 server
21. 974843 Exchange Server 2007 performance counter “Messages queued for submission” shows incorrect value
22. 974897 You receive an NDR you try to send messages through your Microsoft Exchange Server 2007 account
23. 974946 Exchange Server 2007 OWA users receive an error message when the users change the display line for the search results on the address books
24. 974999 The “Task Owner” field is not set when you create a task in Outlook Web Access
25. 975050 A call transfer fails by using key mapping in a mixed Exchange Server 2007 UM server and OCS 2007 environment
26. 975165 EWS proxying requests fail after you run Availability Service requests in a CAS to CAS proxying scenario in Exchange Server 2007
27. 975213 You cannot log on to your mailbox and you receive an error in an Exchange server 2003 and Exchange Server 2007 coexist environment
28. 975255 Event 2104 and event 2147 are continuously logged in an Exchange Server 2007 Cluster Continuous Replication (CCR) environment
29. 975404An attachment of a meeting request cannot be opened when you use a CDO application to accept a meeting request in Exchange Server 2007
30. 975844 The misspelled word of a message loses its custom format when an Exchange Server 2007 user writes the message in OWA
31. 975903 The RemoveDelegate operation of EWS fails, and then a “500 internal server” error response and event ID 4999 are logged in an Exchange Server 2007 server
32. 975916 The custom form of a meeting request is removed in the recipients’ calendar in an Exchange Server 2007 environment
33. 975918 When an IMAP4 client sends a FETCH (bodystructure) request to a server that is running the Exchange Server 2007 IMAP4 service, a corrupted response is sent as a reply
34. 975946 An S/MIME message is not verified and is rejected when BizTalk Server 2006 uses the Exchange Server 2007 version of ExSMime.dll to parse MIME messages
35. 975990 Messages that have duplicate message IDs are deleted when they are archived to an Exchange 2007 mailbox
36. 976025 The free/busy information of an Exchange Server 2007 user is not displayed
37. 976106 Microsoft Exchange Transport services crashes with StackOverflowException when Message Journaling is enabled on Exchange Server 2007
38. 976107 You receive the warning “Failed to update recipient” when you run the Update-addresslist cmdlet in Exchange Management Shell on Exchange Server 2007
39. 976137 Exchange Server 2007 Unified Messaging incorrectly plays a nonbusiness hours greeting when someone call during holiday
40. 976195 You cannot edit a transport rule if one or more of the recipient addresses are disabled or removed in an Exchange Server 2007 server
41. 976653 The Cluster Administrator shows that the mount operation fails and error 1003 is logged even though the database is mounted in an Exchange Server 2007 CCR or in a SCC environment
42. 976787 The Calendar Month View displays a numeric date and not an abbreviated month name when you set the Regional Settings to Japanese or to Korean in Outlook Web Access for Exchange Server 2007
43. 976794 When you edit an e-mail message in OWA, the font changes to the default Internet Explorer font
44. 976946 The message delivery time is incorrect when you send e-mail messages by using an IMAP4 client together with the APPEND command in Exchange Server 2007
45. 977085 An incorrect value for DumpsterMessagesDeleted is reported in an Exchange Server 2007 environment
46. 977091 The time for an updated meeting request is incorrectly shown in an exception instance of a recurring meeting request on an Exchange Server 2007 environment
47. 977181 The EXOLEDB component is not initialized successfully when you start Exchange Information Store Service on an Exchange Server 2007 server
48. 977223 A move operation on a folder fails when the “ptagProvisionedFid” attribute is invalid in an Exchange Server 2007 environment
49. 977261 One or more errors occur when you set the Message Access logging level to Expert in an Exchange Server 2007 SP2 server
50. 977355 Non-ASCII characters in a display name of a forwarded message are shown with “?” when the display name of a contact is in East Asia characters in an Exchange Server 2007 environment
51. 977412 Error message when you use the WebDAV protocol to connect to an Exchange Server 2007 server: “Error 1000”
52. 977425 The “Proxy server name” field is incorrectly shown in OWA in an Exchange Server 2007 CAS-to-CAS proxy environment
53. 978593 Windows Server 2008 VSS backup plug-in fails to backup Exchange 2007 Service Pack 2 databases that reside on a volume mount point

To download the x64 or x86 version of the patch click here.

I’ve updated the Exchange versions, builds and dates table accordingly. You can find it here.

The Microsoft Exchange Team released an update of the (take a deep breath) Exchange 2010 Mailbox Server Role Requirements Calculator. The latest version is 3.2 and it includes new features, improvements as well as some fixes. Here are some of the changes since 1.2:

• Hub Transport & Client Access Server core calculations;
• Possibility to change the number of databases;
• Support for 2-node site resilient DAGs;
• 1 & 6 core options;
• RAID 5 & 6 non-selectable for low-RPM drives;
• Conditional formatting to warn for misconfigurations.

For the complete changelog consult the version changes sheet. Note that the new calculator doesn’t support the Active/Active scenario. When required, it is suggested to use two calculation files:

1. One for the Primary site using the Seconday site as Disaster Recovery site;
2. One for the Secondary site with the Primary site as Disaster Recovery site.

To download the Exchange 2010 Mailbox Server Role Requirements Calculator
v3.2 click here.