Friday, November 12, 2010

The WADMigrator Warm and Fuzzies

Acitve Directory Migration With Minimal End-User Impact.

The Winzero Active Directory Domain Migrator was designed with least end user impact foremost in mind. This was achieved by reducing any impact on the source domain during the migration process.

By understanding the processes involved during each migration phase is to understand that at any time during the migration the source domain remains untouched until the final step where the end user’s account is enabled in the target domain and their workstation is cut over to join the target domain.

Migration Steps
During the account, contact and group migration, new accounts are created in the target domain, accounts are not moved. The new security accounts in the target domain all have new SIDs and their original SIDs are appended to each target account’s SIDHistory. NO impact on source accounts.

Once the accounts and groups are recreated in the target domain, their SIDs are matched in an account migration table with the original source accounts for both users and groups. The table is laid out in four columns: source UNCName, target UNCName, source SID and target SID. Once again NO impact on source accounts.

After the migration tables are created, all resources in the source domain, servers and workstations, are reACLed by appending the target name or SID to each object thereby creating a state of co-existence between all objects in the source domain and target domain. In other words; regardless whether the source or target account is trying to access any resource: files, folders, shares, profile objects or email, both accounts have the same access to each resource. Again NO impact on source accounts.

During the final phase of the migration, referred to as the cutover, workstations and/or servers are migrated to the target domain. During this process the source accounts of the selected users are disabled and their target accounts are enabled just prior to moving the accounts workstation to the target domain. The workstation reboots and joins the new domain. This is the only impact on the source domain: the user account is disabled and the computer is moved to the target domain.

Rollback Plan
If for any reason the migration or subset of a migration must be reversed, WADMigrator would be used to:
A) enable the source accounts, disable the target user accounts and
B) migrate the migrated workstations back to the source domain.
All the original source domain user accounts and group accounts with the original rights and permissions still exist, untouched in the source domain.

During all phases of the migration the source domain is not touched or restructured in any way. Only until the source domain controllers are removed will the properties of the source domain cease to exist in its original form.

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