Checksum Mismatch Error:
Exchange server as versatile and effective as it seems, faces common errors and limitations leading towards complete failure .Errors such as Dirty shutdown, hardware error etc are amongst the few causes that leads to exchange server failure .Every process that is under execution maintains a checksum report that tells what is working correctly and what is not. It also generated caution reports stating such as:” a database page read has failed verification due to checksum mismatch” and halts other process execution. The error also defines that the database pages referenced within the exchange store files such as priv1.edb got corrupted.
This error leads users towards the following issues such as: “Unable to send or receive messages”, Outlook client won’t start or the online backup process aborts at the last moment and shows a checksum error .Checksum error is triggered only when there is an issue in establishing the connection or authentication failure. Henceforth the error point out towards an issue to store or retrieve data from current Exchange Server database .But there are chances that the database is still not damaged and the error is simply triggered by firmware malfunction.
To avoid future issues, following these steps might be actually useful:
- Perform thorough inspection, by proofreading the log events.
- Upgrading the firmware and disk controller BIOS to latest vendor specific versions- Upgrading always ensures that the information getting stored is safe and is using a better technology.
- Troubleshooting hardware issues or upgrading the hardware: Hardware health is a crucial factor for exchange database, if your hardware is not healthy then you might often face issues .It is recommended to upgrade hardware after every 2 year gap.
- Execute System diagnostic tests and repair the frequent errors: This scans the disk sectors for accessibility issues and tries to troubleshoot them with utmost precision.
- Perform disaster recovery: Every organization has to maintain a hot backup of the current data, in case of a disaster. If you still have a healthy backup file, then restore the data.
Using Database Repair Tools:
This tool has the capability of scanning and locating the errors in the given database. It then successively repairs the detected errors. ISINTENG can be executed from ../Program Files / Exchsrvr
ESEUTIL /P: In case of a database file error, repairing the damaged file should be the first and foremost step after diagnosing errors. To repair the database we use ESEUTIL /p command .It works by first detecting the corrupted pages, deleting them and creates a blank void in that space
Here’s a diagram depicting EDB file storage, page location, numbering and location of the corrupt pages.
ESEUTIL /D: Defragmentation helps organize the repaired database files or helps adjusting free spaces. Exchange server performs automatic defragmentation every night, but it is limited to online databases only. To reduce database size online defragmentation is a complete waste of time, perform offline defrag instead using ESEUTIL /d command.
Here’s a Diagrammatic Representation of How The Defragmentation Process Works:
After repairing the database, we found out white spaces at the corrupt area. Defragmentation process removes those white spaces and them labels them according to their physical number.
The white spaces have been eliminated and the healthy pages take up the white space area.