How to recover an exchange server after a major failure: A step-by-step approach
Emails are a crucial element of communication when it comes to business. If you are running an Exchange Server, it is vital to make sure that the server runs properly to ensure uninterrupted email communication. There are many things that can happen to an Exchange Server. When a disaster strikes, you need to ensure that the server is recovered in the least possible time, with minimal disruption and no data loss. In this guide, we will see how to recover Exchange Server and the data after a major failure.
In case of Exchange Server failure, the major concern of admins is recover the server within minimum time and without data loss. You can follow the below given steps to recover the server after failure within minimum downtime.
Pre-Recovery Checklist
In case of failure or any issue, you must first go through the following checklist:
- Check the Event Viewer and the Exchange Server logs to confirm the extent of damage and allocate some time to troubleshoot, before going for a full rebuild.
- Confirm that the backups are in order and available, in case a full restore is needed.
- Confirm that the documentation of the server is fully updated. Ensure that the Operating System, Exchange Server version, and Cumulative Update level are updated, and roles are defined.
- Have all the media and licenses in hand so that the server can be rebuilt to the same specifications and software level.
- Confirm that the disaster recovery document is in place and the required people are informed and the teams are engaged.
- Make sure to have a copy of the certificates used on the Exchange Server, with respective passwords.
Rebuild the Exchange Server
Rebuilding the Exchange Server involves creation of the same environment. As all the configuration is stored in the Active Directory Schema, you can use the recover server process to rebuild the same server. However, it is to be noted that certificates and custom send/receive connectors are not stored in the Active Directory Schema.
When rebuilding the server, the first part is to reset the computer account from the Active Directory Server using the Active Directory Users and Computers. For this, right-click on the computer name and click on the Reset Account. This will allow you to join the Active Directory domain using the same computer name.
From the documentation, you can build a server with the following specifications:
- Same operating system
- Same server configuration in CPU, drives/letters, memory, network cards/VLANs, and other specifications
- Same computer name and IP addresses
Once this is complete, you should join the server to the Active Directory domain. Once this is complete, you can get the installation media of your Exchange Server and run the setup.exe file using the recoverserver parameter.
Although you would not see much activity, the server will be installed and reconfigured from the configuration found in the Active Directory Schema. The installation will take around 45 minutes, depending on the performance of server. Once this is done, you will have an operational Exchange Server without any mailbox data.
Recover the Databases
The next step is the recovery of databases. Since you have the same data drives with the corrupted or orphaned databases, the Exchange Server will fail to mount the databases. In this case, you can try using the EseUtil command to change the database state from Dirty Shutdown to Clean Shutdown.
You can run the below command to check the state of database.
eseutil /mh “M:\ExchangeDatabases\DB01\DB01.edb”
If the state is Dirty Shutdown, you can start by trying soft recovery using the command as given below.
eseutil /r E00 /l “M:\ExchangeDatabases\DB01\Logs” /d ” M:\ExchangeDatabases\DB01″
This command will replay the transaction logs in the folder and try to bring the database to a consistent state. After the command is completed, you can recheck the state of database. If the state is Clean Shutdown, you can mount the database.
In case the database state is still Dirty Shutdown, you can use the hard recovery mode but it is highly not recommended. This will guarantee data loss as it will create a new database and literally purge any items which are deemed as corrupted. In addition, it will take an extensive amount of time and storage to complete.
An Alternative Solution to Recover Databases
If the databases are corrupted, soft recovery can only fix minor corruption issues and hard recovery can result in data loss. On the other hand, recovering databases from backup will also result in data loss – from when the backup was taken to when the server failed. However, specialized Exchange database recovery tool, like Stellar Repair for Exchange, can reduce the recovery time to a minimum and guarantee recovery of databases.
The tool supports all versions of Exchange Server and can open any database of any size and in any state, without the need of a running Exchange Server. After a quick or extensive scan, you will be presented with the full structure of database. You can granularly export user mailboxes, user archives, shared mailboxes, disabled mailboxes, and public folders, to PST and other file formats. You can also export the EDB file data directly to a live Exchange Server database of any version with automatic mailbox matching, priority export, and parallel exports. The tool can also be used to migrate mailboxes and public folders to Microsoft 365 (Exchange Online).
Conclusion
When there is a major disaster on Exchange Server – be it standalone or with a high availability (Database Availability Groups), you must ensure that it will be recovered within the least possible time and without any major data loss. Though you can easily rebuild the Exchange Server, recovering databases without data loss is a challenge. Restoring databases from backup can result in data loss. For quick recovery of databases without data loss, you can take the help of an Exchange repair tool, such as Stellar Repair for Exchange. This tool can repair corrupted database (EDB file) of any size and recover all the mailboxes and other items with complete integrity.
Bharat Bhushan
Stellar Data Recovery
