Infrastructure Impact

You should analyze the impact on the infrastructure that the migration will make to prepare the stakeholders in advance. This will allow them to understand the severity of the impact and a time period when it will occur so they can make appropriate plans. Migrating from Windows NT undoubtedly will have a greater overall impact than migrating from Windows 2000 because the majority of the impact would have been absorbed in the Windows NT to 2000 migration. The impact can be divided into five categories:

• Network : The network can be affected by replication traffic (placement of GCs and DCs), DNS implementation (integration with existing company DNS structure), and bandwidth utilization by Terminal Services clients if you are using Terminal Services. This is predictable because Windows 2000 only replicates changes and then on an attribute level ”usually very small bits of data. As noted in Chapter 1, Windows Server 2003 now refines that replication for some multivalued attributes, so that only the changes in the list of values is replicated, which further reduces the load on the network. Numerous improvements in AD replication make 2003 replication even more efficient.

• User groups : Not much change here from Windows 2000. A brief discussion in the document is presented to describe how universal and domain local groups as well as group nesting can be used in a multiple-domain forest to add additional user access options across domains. You should get a good summary of all current groups defined in the current environment, even if you are at Windows 2000. Things change, and this is a good time to eliminate those unused groups everyone has forgotten about.

• System environment : The impact to the hardware in terms of upgrades could be significant. Prepare the customer (or your management) here with a summary of current hardware versus the HCL. This was already listed previously in the "Servers" section in this chapter. However, Windows 2003 Server will usually perform well on a server that performs well with Windows 2000.

• Security systems and implementation : Using Table 4.7, identify key features in Windows 2003 security that should be considered for the new environment. For instance, if you believe that implementing a PKI will be important to the company, note that here. Again, you are preparing for the recommendations section.

• Backup strategy and operations : Identify the backup software being used currently and note that it must be tested prior to the migration. Note also that Microsoft has developed some excellent strategies recently for backup and recovery of the environment. This includes recovery of a single DC, a GC, a domain, and an entire forest via backup media. If you have a disaster recovery plan that has not been reviewed for a while, you might want to compare it to Microsoft's current standards. Note that current strategy covers the reconstruction of an entire forest from tapes stored off-site.

note

There are a number of critical issues regarding restoring domain objects, not all of which are documented particularly well. HP's Consulting and Integration Services have been very active in identifying these issues and solutions. Chapter 11, "Disaster Recovery," contains more detailed information.