Knowing Exchange Server Corruption and Exchange Recovery

November 9, 2009 Solving Exchange Server Errors

Exchange database administrators can experience Exchange database failure due to physical corruption or logical corruption. Logical corruption is more problematic than physical corruption and requires a lot of expertise to get back the database to a consistent state. Depending on the type of database corruption and symptoms, different tools and techniques are required to diagnose and solve the problem. Let us know more about Physical corruption and logical corruption of Exchange server database:

Physical corruption: Physical corruption occurs due to faulty hardware that usually corrupts the data on the hard disk.

Logical corruption: Logical corruption can occur at the database level or at the application level. At the application level, corruption occurs in mailboxes, messages, folders and attachments due to page corruption, dirty shutdown or checksum issues.

Detecting and resolving physical corruption

Physical corruption in the information store generates the following errors:

  • -1018 (JET_errReadVerifyFailure) The data read from disk is not the same as the data that was written to disk.
  • -1022 (JET_errDiskIO) The hardware, device driver, or operating system is returning errors.
  • -510 JET_errLogWriteFail The log files are out of disk space or there is a hardware failure with the log file disk.

The only way to recover data in case of physical corruption is to recover from the latest backup.

Detecting and resolving logical corruption

Logical corruption is unpredictable and is typically caused by software bugs. It is more dangerous than physical corruption.  Whenever your Exchange database gets logically corrupt, it generates the following error message:

  • 614. All future database updates will be rejected. Information Store (3420) Unable to rollback operation #65678740 on database C:\EXCHSRVR\mdbdata\priv1.edb.
  • Error -528 initializing the Microsoft Exchange Server Information Store database
  • All types of Jet engine errors

Logical corruption can be dealt with Isinteg and Eseutil utility that are provided by Microsoft. With Isinteg utility, you can check the problems occurring in the information store and with Eseutil utility you can diagnose and fix the problems occurring in the jet database engine. But these two utilities have limited functionalities that do not prove fruitful in severe database corruption scenarios.

In severe database corruption cases, Exchange recovery software are the only solution that you need to look upon. These software are embedded with powerful scanning algorithms to ensure absolute recovery of your inaccessible data from EDB file of Exchange Server. At present many Exchange recovery software are available in the market. But selecting the Exchange recovery from a huge list of recovery software is not an easy task. So be cautious and tricky while selecting the Exchange recovery tool.