Regardless of the method that is chosen to migrate
Exchange, care should be taken to test design assumptions as part of a
comprehensive prototype lab. A prototype environment can
help simulate the conditions that will be experienced as part of the
migration process. Establishing a functional prototype environment also
can help reduce the risk associated with migrations. In addition to
traditional approaches for creating a prototype lab, which involves
restoring from backups, several techniques exist to replicate the
current production environment to simulate migration.
Creating Temporary Prototype Domain Controllers to Simulate Migration
Construction
of a prototype lab to simulate an existing Exchange infrastructure is
not particularly complicated, but requires thought in its
implementation. Because an exact copy of the Active Directory is
required, the most straightforward way of accomplishing this is by
building a new domain controller in the production domain and then
isolating that domain controller in the lab to create a mirror copy of
the existing domain data. DNS and global catalog information should be
transferred to the server when in production, to enable continuation of
these services in the testing environment.
Note
You
should keep several considerations in mind if planning this type of
duplication of the production environment. First, when the temporary
domain controller is made into a global catalog server, the potential
exists for the current network environment to identify it as a working
global catalog server and refer clients to it for directory lookups.
When the server is brought offline, the clients would experience
connectivity issues. For these reasons, it is good practice to create a
temporary domain controller during off-hours.
A
major caveat to this approach is that the system must be completely
separate, with no way to communicate with the production environment.
This is especially the case because the domain controllers in the
prototype lab respond to requests made to the production domain,
authenticating user and computer accounts and replicating information.
Prototype domain controllers should never be added back into a
production environment.
Seizing Operations Master (OM) Roles in the Lab Environment
Because
Active Directory is a multimaster directory, any one of the domain
controllers can authenticate and replicate information. This factor is
what makes it possible to segregate the domain controllers into a
prototype environment easily. There are several different procedures
that can be used to seize the OM (also referred to as Flexible Single
Master Operations [FSMO]) roles. One approach uses the ntdsutil utility, as follows:
1. | Open a command prompt by selecting Start, Run, typing cmd in the Open text box, and then clicking OK.
Caution
Remember,
this procedure should only be performed in a lab environment or in
disaster recovery situations. Never perform it against a running
production domain controller unless the intent is to forcibly move OM
roles.
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2. | Type ntdsutil and press Enter.
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3. | Type roles and press Enter.
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4. | Type connections and press Enter.
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5. | Type connect to server
SERVERNAME (where SERVERNAME is the name of the target Windows Server 2003 domain controller that will hold the OM roles), and press Enter.
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6. | Type quit and press Enter.
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7. | Type seize schema master and press Enter.
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8. | Click Yes at the prompt asking to confirm the OM change.
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9. | Type seize domain naming master and press Enter.
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10. | Click Yes at the prompt asking to confirm the OM change.
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11. | Type seize pdc and press Enter.
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12. | Click OK at the prompt asking to confirm the OM change.
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13. | Type seize rid master and press Enter.
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14. | Click OK at the prompt asking to confirm the OM change.
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15. | Type seize infrastructure master and press Enter.
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16. | Click OK at the prompt asking to confirm the OM change.
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17. | Exit the command prompt window.
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After
these procedures have been run, the domain controllers in the prototype
lab environment will control the OM roles for the forest and domain,
which is necessary for additional migration testing.
Note
Although
the temporary domain controller procedure just described can be very
useful toward producing a copy of the AD environment for a prototype
lab, it is not the only method that can accomplish this. The AD domain
controllers can also be restored via the backup software’s restore
procedure. A third option—which is often easier to accomplish but is
somewhat riskier—is to break the mirror on a production domain
controller, take that hard drive into the prototype lab, and install it
in an identical server. This
procedure requires the production server to lose redundancy for a
period of time while the mirror is rebuilt, but is a “quick-and-dirty”
way to make a copy of the production environment.
Restoring the Exchange Environment for Prototype Purposes
After
all forest and domain roles have been seized in the lab, the Exchange
server or servers must be duplicated in the lab environment. Typically,
this involves running a restore of the Exchange server on an equivalent
piece of hardware. All of the major backup software implementations
contain specific procedures for restoring an Exchange 2000 environment.
Using these procedures is the most ideal way of duplicating the
environment for the migration testing.
Validating and Documenting Design Decisions and Migration Procedures
The
actual migration process in a prototype lab should follow, as closely
as possible, any design decisions made regarding an Exchange Server
2003 implementation. It is ideal to document the steps involved in the
process so that they can be used during the actual implementation to
validate the process. The prototype lab is not only an extremely useful
tool for validating the upgrade process, but it can also be useful for
testing new software and procedures for production servers.
The
chosen migration strategy—whether it be an in-place upgrade, a move
mailbox method, or another approach—can be effectively tested in the
prototype lab at this point. Follow all migration steps as if they were
happening in production.
