The Prep Forest step requires a decision on the location for OCS Global Settings – you can choose to store these in the System container in the root domain (default and recommended) or the Configuration partition which is replicated Forest-wide. Refer to the OCS AD guide for addition detail on Active Directory Global Settings and Objects. http://technet.microsoft.com/en-us/library/bb803604.aspx
Factors to consider for storing OCS Global Settings:
- Do you have LCS? If you do, the configuration partition option selection will be grayed out - choose the domain partition. If you have server or MMC performance problems related to access to the root domain, follow the Tip below to move to the configuration partition.
If LCS/OCS is running into issues because of poor root connectivity – this typically shows up in poor MMC performance and errors in LCS/OCS server event logs – you can remove LCS/OCS from the forest and then rerun Prep Forest choosing the configuration partition. To remove LCS, first deactivate and remove all LCS and OCS servers, remove Prep Domain configuration (use the DomainUnPrep Action with LCSCmd.exe) and remove Prep Forest configuration (use the ForestUnPrep Action with LCSCmd.exe).
- Do you have a mature Exchange implementation? If you do, you are already replicating Exchange configuration settings Forest-wide so adding OCS configuration will not significantly impact your network – choose the configuration partition.
- Do you have a Distributed Forest with Domains or Sites where you will deploy OCS servers (all roles - Front End, Mediation server, etc. - except edge servers which are not domain joined) that do not have a reliable and fast connection to a root domain DC? If so, choose the configuration partition.
- Do you have an empty root (a root domain that does not host users or servers) in your Forest? If so, you can run into issues deploying OCS servers in child domains at a site without reliable and fast connectivity to a root domain controller. This is similar to #3 above – choose the configuration partition.
- Is this a Greenfield installation? If this is a new installation without LCS, Exchange or a complex Forest, then go with the default and recommended root domain naming context storage as this will reduce AD replication traffic on your network. If you have a distributed deployment with sites/domains that now or in the future will house OCS servers without good and fast connectivity to at least one root domain DC/GC, you are in the same situation as #3 or #4 - choose the configuration partition.
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