Exchange has many tools that come from Microsoft to aid you in repairing your system in the even that something bad happens. The utilities can attach individual mailboxes to a system, and they can even repair the Database in the event that a serious failure occurs. Although these are all utilities that you can use to recover Exchange in the event of certain problems, this review would not be complete without an explanation of a fascinating new recovery option called Disaster Recovery.
One of the last things that you ever want to hear from a person in the Exchange department is, “Oh Shoot,” when they look at the Exchange Server. Those words can stop you heart. But let me help you to understand some PRO-ACTIVE measures that you can take to have your system ready to be recovered in a worst-case scenario. First, let’s discuss the five steps necessary to restore your system from a COMPLETE failure. Note: You have to BACKUP your system before a disaster occurs!!! If you install Exchange 2000, immediately setup a backup schedule and activate it. Otherwise, you may find yourself very upset, and perhaps looking for another job.
1. Reinstall Windows 2000 – Wipe the drive and reinstall Windows 2000.
2. Restore you System drive – Restore the system from a previous backup. For obvious reasons.
3. Restore the Windows 2000 System State – This will configure Active Directory on your server the way it was before the failure. This step is VITAL for disaster recovery to work.
4. Run Exchange 2000 Server Setup with the Disaster Recovery Switch – This will take the configuration information in Active Directory about your server and apply it to your local machine.
5. Restore the Information Stores – Finally restore the Databases from the application that you backed them up from.
Now, if you have been doing your job right, then this whole process will be a breeze. But in reality, according to Moore’s Law, that usually won’t happen, so you need to know how to help yourself in the event that one of these steps can’t be done. The first thing that you could have forgotten to do is BACKUP YOUR SYSTEM DRIVE. This one is not as serious as the others; they actually get more catastrophic as you move down the list. This problem can be fixed by simply reinstalling all of your applications and service packs.
The second problem that you can commonly run into if you aren’t careful is if you forget to back up your System State Data. This is a much more serious problem because if you only have one AD Server, then you have lost ALL Directory information. You will have to recreate users, computer accounts, groups, etc… If you have other domain controllers then the process may not be as bad. To reinstall the server with the same server name, you will have to remove all information about the server’s existence in Active Directory using ASDI Edit. This is a very dangerous task and I suggest that you have Microsoft Product Support on the phone at this point.
The third issue is usually related to the previous one. If you did not do a System State backup and simply delete the Domain Controller’s computer account in Active Directory, then reinstall the DC with the same server name as the old server, when the Exchange 2000 Setup program begins, it looks to AD for configuration information and determines that it already has Exchange Server installed, thereby initiating Disaster Recovery in the setup of Exchange. Disaster Recovery is an option in Exchange 2000 Server’s setup application that can be initiated if the Server is listed in Active Directory as an Exchange Server. Essentially, this option will only repair the Exchange 2000 Server’s installation, it does not install Exchange. Exchange will not install properly. To resolve this, you must remove all signs in AD that Exchange ever existed on that server, which is a very delicate task. Again, Microsoft Product Support would be helpful in this situation.
Finally, you must restore the databases. This process can be simple or extremely difficult, depending on whether you did your backup or not. If you backed up your Exchange databases, then restore them with the same backup utility you used to set them up in the first place. Usually the Server will start back up and you will not have many problems. But, if you never backed up your Exchange databases and you still have access to the Information Store databases and log files, you can do an “Offline Restore.” This method of restoring Exchange is VERY complex.
The Offline Restore
This is the nightmare of Exchange administrators. The worst thing that you can have to deal with is using this method to restore your Exchange server. I am not going to go into it because it can become a lengthy explanation, so I will refer you to the knowledge base articles at the bottom of this page for more info. If you never backed up your Exchange server and you had turned off circular logging immediately, then you can do what’s called an offline restore with the log files. This involves using an interesting utility called ESEUtil. You will have a lot of fun with this. I have had to restore an Exchange Server once in this scenario and I promise you that it is possible, but difficult. To find more information on ESEUtil and Isinteg, look on you Exchange 2000 Server CD Rom for a file called ESEUtil.rtf and another called Isinteg.rtf. Those are little documents from Microsoft that explain these utilities.
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