Step By Step Guide To Repair Exchange 2010 Database Corruption

 

Exchange server 2010 database is a stable database that the earlier versions, but corruption do happen when you less expect it. Corrupted database is no less than a nightmare for an Exchange administrator. Although, administrators do have the option to restore or repair the database, but this is not as easy as it seems to be. Even a slightest mistake can render the entire database in a state far beyond repairing. In this blog post, we will have put together the different types of database corruption issues in exchange server and the remedial procedures to repair Exchange 2010 database corruption.

 

Real Time Scenario Of Exchange 2010 Database Corruption

 

One of the most probable scenarios of Exchange database corruption is when the hard drive storing the Exchange server poses issues and ultimately corrupts the mailbox data. What exactly happens is that the original file size is not shown and instead of it 0 KB is displayed. Moreover, the Exchange server does not mount the database. Scenarios like above, lead to overall corruption of Exchange database.

 

Kinds Of Corruption In Exchange 2010 Database

 

Although Exchange data (mailboxes) is saved in databases that are less prone to corruption, there are times when the inevitable happens. Corruption in Exchange 2010 can be broadly classified under following categories:

 

Logical corruption

 

Logical corruption is often referred as Application or Database level corruption. Application level corruption arises when the corruption is found in mailboxes, mails, attachments or folders. In the same way database level corruption is observed when the database gets damaged. Moreover any damage or failure in Extensible Storage Engine is also considered as database level corruption.

 

Physical Corruption

 

Hardware failures or defects lead to physical corruption aka page level corruption of Exchange database. Also at times the log files of Exchange database are in a disheveled order and go out of disk space, hence leading to physical corruption. Other reasons like differences in the read and written data also cause corruption.

 

Pre-Requisites Before Repairing

 

    1.    First of all, make sure that your database is not really starting. At times, it happens that the database is safe but there is some other issue. Restart the server. Maybe the issue which is getting in the way will get cleared and you will not need to indulge in the repairing process.

 

    2.    Make sure to make a backup copy of the database before starting with the repairing process.

 

    3.    There should be enough space in your hard drive to do the repair. Conventionally, free space should be at least 20% of the size of database. if not, use command line switches to shift the temporary files in a different drive.

 

In-Built Utilities To Rescue Exchange 2010 Database

 

Once corrupted, the only option left with the users is to search for method to repair Exchange 2010 database corruption. Fore sighting the corruption issues in database, Exchange provides two inbuilt utilities so as to support the users in their repairing process-Isinteg and Eseutil. If the data within your corrupted database is in a salvageable state, then the two utilities can surely bring back your data.

 

    1.    Isinteg

 

        a.      Information Store Integrity checker is a utility to check mailbox and public folders database. From Exchange 2010, Isinteg is no longer a standalone utility. From now onwards, the Isinteg functionality is split into two Exchange Management Shell cmdlets-

 

    2. New-MailboxRepairRequest


    3. New-PublicFolderDatabaseRepairRequest


    4.    The new features which are supported by Isinteg are:

    5.    There is no need to dismount the database for repairing or for performing integrity check.

    6.    Logical corruptions can be repaired at mailbox level.

    7.    Corrupt search folders can be repaired.

 

           a.    Aggregate counts can also be repaired.

 

    1)   Eseutil

 

You can also repair Exchange 2010 database corruption with Eseutil command. Before running Eseutil command, make sure that both the database files i.e. the STM file and the EDB file are on the same directory. This will make the repair process easier. The default location of Eseutil is \exchsrvr\bin when Exchange is installed. The following command when run will repair DB1.EDB file located in C: Drive with its companion TSM file located in D: drive.

Eseutil /P d:\exchsrvr\mdbdata\DB1.EDB /Sc:\exchsrvr\mdbdata\DB1.STM

 

After this, run Eseutil in defragment mode. Repair process leaves the index and allocation space issues in the database. Defragmentation compact the physical size of the database and also rebuilds space trees and indexes.

 

Alternative Solution To Repair Exchange 2010 Database Corruption

 

At times it happens that the inbuilt utilities of Exchange server 2010 fail to repair the corrupted database. Therefore as an alternative, one can take help of third party tools. One such tool is Exchange Recovery software. The tool successfully recovers both offline and dismounted EDB files. Also it supports recovery of deleted Exchange mailboxes. It supports recovery of Exchange 2010 as well as corrupted mailboxes of earlier versions of Exchange server and also converts EDB file into PST format which allows an easier access of Exchange emails into Outlook platform.