Disaster Recovery – Mailbox Server

There will a day where you need to replace the existing server with the new server just because of bad hard drive or some sort of corruption. Actually here you don’t want to reinstall the whole stuff back but what you need is that the new server which will the identical information should have the information back by minimal impact of time. In this sort of situation Microsoft came up with the method of disaster recovery switch after the release of exchange 2000 and it is the switch which is known by each and every administrator.

What is Disaster Recovery?
 Disaster Recovery is nothing but a switch which will help the administrator to grab the information from Active Directory and place all the missing files in the new server which has the same identical as like we had in the old server.

Before the release of Exchange 2007, we had to follow this command to recover the exchange application back i.e setup.exe /disasterrecovery. But after the release of exchange 2007 the concept is same but the switch model has been changed i.e instead of using setup.exe /disasterrecovery  we need to use
Setup.com /m:RecoverServer or Setup.com /Mode:RecoverServer (unattended method)

I would like to share my point of view how we can get back our database in the new hardware which will have the same identical.

In this article I will give you the brief idea about the backup method, which are files we need to take the backup, how to bring back our exchange application on the new server and restoring the database.

Brief Knowledge Sharing about Backup:
If we come across in a situation where our database gets corrupt or server crashes what will be our next plan. If you get the data back online then you will become a star. Whatever may the reason for disaster but the only option you rely most of the time during disaster is backup as a backbone for us. So you can imagine how important to maintain the backup of the database.

In this session we will have brief idea about backup strategy of exchange 2007.
Methods for Database Backup:
There are two types of backup strategy:
1) Legacy Streaming backup: This method uses the Extensible Storage Engine (ESE) application programming interface (API). This is to be one of most usable backup strategy in the today’s trend and it is being used from all previous Exchange version plus other backup vendors. Eg: NTbackup.

2) Volume Shadow Copy Service: Support for Volume Shadow Copy Service (VSS) was introduced in Exchange Server 2003 and enhanced extensively in Exchange 2007. Microsoft does not provide an Exchange-aware VSS-based backup solution. The Windows Server 2003 Backup utility does not support VSS. Backup can take VSS shadow copies of the Exchange database and log files, but this is done at the file level. These copies are not Exchange-aware backups. Third-party backup software is required to back up the Exchange database with VSS. You must buy an Exchange-aware backup solution to take advantage of VSS functionality.

Certain objectives need to set while we are planning for backup:
1) Which are the resources will be used during the backup like CPU utilization, I/O, Performance issue during that course of time and network bandwidth utilization.
2) Time duration of the backup.
3) Which are things need to backup and last set of backup like need to decide what mode of backup we are going to use, if any disaster occur how much data we can recover? Microsoft recommendation is to take daily backup.
4) Service Level: if any disaster occurs how much time it will take for restoring the backup.

Well this all about basic information regarding backup information which I can share with by the grace of Microsoft TechNet.

Mailbox Server Backup:

Contents which are required to backup:
- System State
- Log files
- Database
- IIS metadata backup

Mailbox server backup is not a new thing for us, we are going to take the backup of the database and log file as we are taking in the previous version from legacy streaming backup:
Figure 1:

Figure 2:

Figure 3:

Figure 4:


If you see the above screen shot there is no change at all as compare to previous version it is as simple as like we did on for Exchange 2000\2003

Disaster Recovery of Server:
Let say one fine day my server crashed, but that doesn’t mean that entire mailbox server information gone from AD itself. AD will have my server information existing in the active directory database.
Figure 5:



So inorder to get my server information back I will bring a new server which will have the same computer name and os & sp then reset computer account. Will install the prerequisite application like powershell, DTC hotfix and .netframework

Then open the command prompt and type the following command
Setup.com /m:RecoverServer
 The above command will contact the Active Directory and will take the information of the configuration data and then it will install the exchange application see the figure 6:


Then mount the database, you will see that we got our application back and even all the mailboxes but with blank database: Figure 7


Now we got the server back but still we need to restore our database. So lets take a walk how to restore the database

Restoration of Database:
 Whenever we are talking about restoration either we can restore the database on the existing mailbox store or else we can use Recovery Storage group. Here I am taking the existing mailbox store method.

• Stop the information store
• Rename the existing mdbdata folder to mdbdataold for log file and database (assuming all in the only one folder)
• Create a new folder called as MDBDATA folder
• Select the option “do not mount the store at the start up” and “This database can be overwritten.
• Click on Start => Run => NTBackup
• Select the option Restore
Note: While restoring it will ask you to create a temp folder for storing the log files create a folder called as Temp in the C route drive. See figure 8:


Note : Keep in mind whenever you do online restore, the database always going to dirty shutdown.
Figure 9:

So here we need to run hard recovery command : eseutil /cc path of the temp folder.
Figure 10:

Once you are done with the restoration of the database, simply mount the store and uncheck “do not mount the database at startup” and “this database can be overwritten”
Figure 11:



Search Index:
The search index can become unsynchronized with the database after a recovery if transaction log files are played into the recovered database. The Exchange search engine does not read the played log files into the search index. In this situation, you should rebuild the search index catalog.

To rebuild the search index catalog, you must stop the Microsoft Exchange Search Service, delete the old catalog, and then restart the service. This action forces the server to re-create the search index catalog.

Summary:
In this article we learnt how to take backup, how to come up with a solution if we face disaster issue, simple restore procedure and rebuilding of search index.

I hope that this article is being informative for you. Thank you for sharing your time.

Related Article:
Disaster Recovery – Mailbox Server
Disaster Recovery – CAS&UM
Disaster Recovery – Hub Server and Edge Server

Reference Link:

Configuring Exchange Server 2007 Preview - Chapter 9: Disaster Recovery with Exchange Server 2007
Database Backup and Restore