Developing a Recovery Plan

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It is important that you develop a recovery plan to prevent accidental data loss during upgrade. This plan needs to detail how you will back up your domain controllers, applications, and other data. How thorough your plan is will determine whether you can completely fall back to the original configuration, if necessary, or whether you have gone past a point of no return. When you are developing your recovery plan, determine if there is a point at which incremental migration can stop and full migration can begin.

Complete the following tasks before you perform your migration:

  • Add a BDC to any Windows NT domain that contains only a single domain controller—the PDC. This will ensure that the domain does not become orphaned if the upgrade to the PDC fails.

  • Determine if services such as file and print services or Dynamic Host Configuration Protocol (DHCP) are running on the PDC and the BDCs.
    Back up these services to tape, and test the backup tapes.

  • Fully synchronize all BDCs with the PDC.

    Take one BDC offline before you upgrade the PDC and the other BDCs to Windows 2000 Server. As a test, perform the following steps before you begin the migration:

    1. Promote the offline BDC to a PDC and check the data.

    2. Keep this PDC offline and available after the migration, and make sure the remaining BDCs are backed up regularly.

caution-iconCaution

Track all changes to the domain (for example, new accounts and password updates) while the offline PDC remains offline. If a disaster occurs with the Windows 2000 domain controllers, it will be necessary to roll back to the offline PDC. If you have not tracked all domain changes made while the offline PDC remains offline, the changes will be lost when the offline PDC replicates its data to the BDCs. Note that recreated accounts have a different security identifier (SID); therefore, they might not have access to some resources.

  • For each step in the flowchart in Figure 10.1, answer the following questions:

    • How would you roll back the system to a recovery state?

    • What administrative tools do you need to accomplish both the upgrade and recovery state?