Reassigning site roles after removing the first server in an Exchange site

The first server installed into an Exchange site by default is assigned several site-wide roles. These roles include:

• Routing calculation server
• Site folder server
• Default site folder replica server
• Offline Address Book generation server

As a best practice, these roles should be re-assigned before the server is removed from the site. This article explains how to re-assign these roles if the first server has already been deleted.

When decommissioning an Exchange server, it is important to inventory and migrate all the data and services provided by that server. It is beyond the scope of this article to provide a comprehensive list of all services and data that may require migration, but some of the more common factors to consider are:

• Mailboxes.
• Public folder replicas, including organization forms.
• Exchange connectors and services, including Key Management Server (KMS) and external directory replication services.
• Third party connectors or other services.
• Connector or replication bridgehead roles.
• Default public folder server role for other mailbox servers.
• Active Directory Connector (ADC) endpoints.

Changing the Routing Calculation Server

The routing calculation server is defined on the Site Addressing object for each site. If you fail to define a new server after deleting the routing calculation server, Exchange will automatically discover the problem and select another server, but this may take several hours or longer. In the meantime, routing information may become out of date.

To change the Routing Calculation Server:

1. Start Microsoft Exchange Administrator.
2. Expand the Configuration object of the site, and then click to select the Site Addressing object.
3. On the General page, click to select a new Routing Calculation Server from those available in the drop down list.

If you have difficulty changing the Routing Calculation Server, please refer to the following Microsoft Knowledge Base article:

Changing the Site Folder Server

If the Site Folder Server is removed from the site, Exchange will automatically discover the problem and select another server, but this may take several hours or longer.

The site folder server has responsibility for verifying the validity and existence of the Offline Address Book (OAB) and the Schedule+ Free Busy (F/B) folders.

The OAB and F/B folders are implemented as public folders in each Exchange site. They are stored in the System Folders public folder hierarchy. They are not directly visible to Exchange users as public folders. Microsoft Outlook clients access these folders through features such as Free/Busy search and Offline Address Book download.

There may be several other folders stored in the System Folders hierarchy, including the Organization Forms library and Events folders for servers with the Event Service installed. These other folders are not checked or managed during the site folder check.

Each time that the Information Store service on the Site Folder Server is started, or once every 24 hours, a site folder check is done. The Site Folder Server removes invalid OAB and F/B folders or generates new site folders as necessary.

As a best practice, the Site Folder Server should hold a replica of both the Offline Address Book and Free/Busy folders. This is not strictly required, but should be considered when deciding which server in the site should be designated as the new Site Folder Server.

To designate a particular server as the Site Folder Server, perform the following steps.Warning If you use the raw mode of the Exchange Server Administrator program (admin /r) incorrectly, serious problems may occur that may require you to reinstall Microsoft Windows NT Server, Microsoft Exchange Server, or both. Microsoft cannot guarantee that problems that result from using raw mode incorrectly can be solved. Use raw mode at your own risk.

1. Start Microsoft Exchange Administrator with the /r command line switch. Admin.exe is in the Exchsrvr\Bin folder by default.
2. Expand the Configuration object of the site, and then click to select the Information Store Site Configuration object.
3. On the File menu, click Raw Properties.
4. In the Object Attributes window, click to select Site-Folder-Server.
5. Click Editor.
6. Replace the existing server name with another valid server name in the same site. For example, if the current Site Folder Server is Server1 and you wish to designate Server2, change
   /o=Organization_Name/ou=Site_Name/cn=Configuration/cn=Servers/cn=SERVER1/cn=Microsoft Public MDB
   to
   /o=Organization_Name/ou=Site_Name/cn=Configuration/cn=Servers/cn=SERVER2/cn=Microsoft Public MDB
7. Click OK to close the Edit dialog box, click Set, and then click OK to commit the change.

Changing the Location of Site Folder Replicas

By default, replicas of the OAB and F/B folders are created only on the Site Folder Server. With regard to replication, site folders behave the same and are managed the same as any other public folder. Administrators can therefore create additional replicas as needed of these folders. As best practices:

• Place replicas of Offline Address Book folders on servers close to the network access points used by remote users who need to download Offline Address Books.
• Limit the number of replicas of the F/B folder to the minimum required for reliable client access. The more copies of the F/B folder there are, the longer it will take for replication to converge the information in all replicas for accurate Free/Busy searches.

If the only replica of the site folders was on a deleted server, then all existing OAB and F/B information was removed with the server. (NOTE: you may be able to recover the information if a backup of the public database on the deleted server still exists and you are willing to reinstall the deleted server into the Exchange site.)

The following error may be seen if the only replica of a site folder has been lost: In this case, you will not be able to access the properties of the affected folders. This prevents you from accessing the Replicas properties and adding a replica to a different server in the site. To work around this problem:

1. Start Exchange Administrator and connect to a server that should hold a replica of a site folder.
2. Click to select the Instances page on the properties of the Public Information Store object for this server.
3. Locate the site folders in the left pane of the Instances dialog box, and then add each folder to the server.

Repopulating the Site Folders with Data

Offline Address Book

To repopulate the Offline Address Book site folder, perform the following steps:

1. Start the Microsoft Exchange Administrator program.
2. Click to expand the Configuration object, click the DS Site Configuration object, and then on the File menu click Properties.
3. Click the Offline Address Book tab, and then click Generate Offline Address Book Now.

Note If an error occurs when generating the OAB, reselect the Offline Address Book Generation server, and try again. If errors still occur, please note the errors and refer to the Microsoft Knowledge Base for more information.

Schedule+ Free Busy Information

The Schedule+ Free Busy Information site folder is automatically repopulated as users log on to their mailboxes and make Calendar changes.

Note Unless public folder affinities have been created with other sites, it will be necessary to replicate the F/B folder throughout your organization in order to allow clients from other site to view Free/Busy information from your site.

Organization Forms

Although Organization Forms are not site folders, they are frequently lost when the first server in a site is removed. Just as with site folders, a replica of the Organization Forms library folder can be placed on another server using the Instances interface on a Public Information Store object in Exchange Administrator. But all forms previously in the library will be lost because the replica will be blank.

For additional information about how to recover the forms in a library without having to reinstall the deleted server back into the site, click the following article number to view the article in the Microsoft Knowledge Base: There should be only one Organization Forms library for a given language per Exchange organization. One site in the organization should host the library, and replicas should be dispersed to all other sites.

As a best practice, place replicas of the Organization Forms library as close as possible to client mailboxes. If a mailbox server has a public folder database on it, a copy of the Organization Forms library should be replicated to that server.

Destroying and Regenerating Site Folders

Do not regenerate site folders unless you have exhausted all other alternatives for recovering replicas of them, or unless you specifically wish to destroy the contents of the existing site folders.

When an Exchange site is created, a Site Folder GUID is generated. The GUID is a 16-byte sequence of hexadecimal characters generated by an algorithm that makes it very unlikely that any other Exchange site in the entire world will possess the same GUID. This GUID is used to name and identify the OAB and F/B folders. When a site folder check is performed, site folders that are based on the wrong GUID are destroyed.

For Exchange 5.5, you will observe a subfolder of the OAB folder called OAB Version 2. This folder contains the Exchange 5.5 version of the OAB. The original OAB folder is used in Exchange 5.5 only for backward compatibility with servers running older versions of Exchange.

The OAB Version 2 folder's name is not based on the Site Folder GUID, and the site folder check cannot remove duplicate or invalid OAB Version 2 folders. But, because the OAB Version 2 folder is a child of the original OAB folder, regenerating the site folders can destroy invalid copies of OAB version 2.

If you are having problems with duplicate site folders, and the site folder check has not been able to correct them, resetting the site folder GUID is usually effective. Doing the following before resetting the GUID will make the process faster and more reliable:

• Replicate the OAB, OAB Version 2 and F/B site folders to the site folder server.
• Remove all replicas of these folders from other servers in the organization.

If you are unable to access the Replicas properties for the folders, use the Instances interface on the Public Information Store objects for each server to accomplish these tasks.

It is possible that by confining all replicas to the Site Folder Server, a site folder check may then be successful without requiring a GUID reset.

In a case where there are duplicate site folders, clients from some servers may have published their free/busy information to one of the folders, while clients from other servers have published their information to a different folder. In such cases, there will be temporary loss of some Free/Busy data from resolving the problem.

The Guidgen utility can be used to generate a new GUID for the site.

Warning If you change the site folder GUID, you must never restore previous backups of any public folder store in the entire Exchange organization. If you do so, you may cause duplicate site folders to be created, cause existing site folders to be destroyed, cause the site folder server's public database to stop replicating permanently, or cause other public stores in the site to be unable to accept replicas of site folders. Correcting such problems may require you to destroy and rebuild public folder stores on some or all servers in the entire Exchange organization.

You cannot reset the GUID for only a single site folder. If you reset the GUID, all offline address books and Free/Busy Information for a single site will be deleted.

To reset the site folder GUID and delete all offline address book and free/busy information in a site, perform the following steps:

Warning If you use the raw mode of the Exchange Server Administrator program (admin /r) incorrectly, serious problems may occur that may require you to reinstall Microsoft Windows NT Server, Microsoft Exchange Server, or both. Microsoft cannot guarantee that problems that result from using raw mode incorrectly can be solved. Use raw mode at your own risk.

1. Obtain a copy of the utility Guidgen.exe.
   
   This utility is available in the Microsoft Developers Network under the product samples. If you do not have access to this utility, contact Microsoft Product Support Services. You do not have to run Guidgen on the Site Folder Server or even on an Exchange server in your organization. Microsoft PSS can remotely generate and send you a new GUID if necessary.
2. Start the Guidgen.exe program, and then click to select Option 4, Registry Format.
3. Click New GUID.
4. The new GUID number is displayed in the Result box. Copy or write down this number.
5. Start the Microsoft Exchange Administrator program in raw mode. Go to the command line, change to the Exchsrvr\Bin directory, and then type admin /r.
6. Click to expand the Configuration object of the site you want to rebuild, and then click to select the Information Store Site Configuration object.
7. On the File menu, click Raw Properties.
8. In the Object Attributes window, scroll down, and then click Site-Folder-GUID.
9. Click Remove.
10. In the Edit Value box, replace the existing GUID number with the number generated in step 4.
    
    If you copy and paste the value generated by GUIDGEN, you may receive the following error message:
    Some of the characters in the clipboard are not valid for this entry.
    Despite this error, the paste will succeed, with dash and brace characters removed from the GUID. If you are manually typing in the GUID, do not enter dash or brace characters.
11. Click Set, and then make sure the Edit Value and Attribute Value are the same.
12. Click Apply, and then OK to close the dialog box.
13. To force an immediate site folder rebuild, stop and start the Information Store on the Site Folder Server. Otherwise, the folders will be rebuilt within the next 24 hours.

If there are multiple servers in the site, the Information Store Services should be restarted on those servers also.

After successful regeneration of site folders using GUIDGEN, the only replicas of the site folders will be on the site folder server. All other replicas throughout the organization will be destroyed as soon as public folder replication completes.

How Site Folder Names Are Constructed

The OAB and F/B folder directory names are constructed in a standardized way using the Site Folder GUID. This allows the Site Folder Server to identify valid site folders. The display names of the folders do not include the numeric string at the end of the name. To see the actual directory name of a public folder, open the properties for the folder in Exchange System Administrator, and check the Directory Name attribute on the Advanced page.

Site folder directory names are up to 64 characters in length. Up to the first 26 characters are constructed from the organization and site names, and then 32 more characters are constructed from the GUID. The last 6 characters of the name are always 000007 for the F/B folder and 000008 for the OAB folder. For example, an OAB folder might have a name like this: The first 12 bytes of the Site Folder GUID are reversed and appended to the stem of the name. Then the last 4 bytes of the GUID are reversed and appended, and then 000008 is added to the end of the name.

If you experience problems with duplicate or mismatched site folders, it can be useful in troubleshooting to determine which folders are the "real" site folders. To construct the names manually, perform the following steps:

Warning If you use the raw mode of the Exchange Server Administrator program (admin /r) incorrectly, serious problems may occur that may require you to reinstall Microsoft Windows NT Server, Microsoft Exchange Server, or both. Microsoft cannot guarantee that problems that result from using raw mode incorrectly can be solved. Use raw mode at your own risk.

1. Start the Microsoft Exchange Administrator program with the /r command line switch. Admin.exe is in the Exchsrvr\Bin folder by default.
2. Expand the Configuration object of the site, and then click to select the Information Store Site Configuration object.
3. On the File menu, click Raw Properties.
4. In the Object Attributes window, click to select Site-Folder-GUID.
5. Copy the GUID to a text editor. In this example, the GUID is 64577DF4E0804473A2CBBD1F0FA02EAA.
6. Separate the GUID into individual hexadecimal numbers as follows:

   64 57 7D F4 E0 80 44 73 A2 CB BD 1F           0F A0 2E AA
   					

7. Reverse the two sections of the GUID for Exchange 4.0 and Exchange 5.0:

   64 57 7D F4 E0 80 44 73 A2 CB BD 1F           0F A0 2E AA   original
   1F BD CB A2 73 44 80 E0 F4 7D 57 64           AA 2E A0 0F   reversed
   					

   
   
   For Exchange 5.5, invert the first four bytes of the original GUID and repeat it three times.
   
   For example, the first four bytes of the original GUID are 64 57 7D F4. Inverting the bytes and repeating them three times results in the following:

   F4 7D 57 64    F4 7D 57 64    F4 7D 57 64
   					

8. Construct the numeric part of the site folder name by adding 000007 or 000008 to the resulting number from the last step.
   
   In this example, for Exchange 4.0 or Exchange 5.0, the folder names are:
   
   EX:_O=ORGANIZATION_OU=SITE1FBDCBA2734480E0F47D5764AA2EA00F000007 (F/B)
   EX:_O=ORGANIZATION_OU=SITE1FBDCBA2734480E0F47D5764AA2EA00F000008 (OAB)
   
   In this example, for Exchange 5.5, the folder name is:
   
   EX:_O=ORGANIZATION_OU=SITEF47D5764F47D5764F47D5764AA2EA00F000007 (F/B)