The main repository of mailbox data in Exchange Server is the .edb file that is primarily composed of b-trees. Since a b-tree is allowed to have a considerable depth, b-trees deploy indexes to permit quick data access. In Exchange EDB, there are few ancillary trees that hold table indexes to work with the main tree. If these indexes go corrupted, the entire table and sometimes, the whole database become unusable. This is what we refer as logical database corruption. In critical situations, when this type of corruption is not limited to index page corruption, you need to implement Exchange Server Repair solutions.
To understand such potential problems with Exchange database further, consider the discussed scenario and error. When using Exchange Server 2007, you can encounter event 467 logging in the application log. Additionally, on viewing the description section of the same event, you receive an error that reads similar to below:
Information Store (number) Index [index name] of table [table name] is corrupted.
This error typically indicates a corrupted index in the Exchange store. As symptoms, you might observe access violations and repeated crashes. Also, this type of corruption might go undetected for long without any symptoms. Even the Exchange-aware backup may fail to detect this corruption. Event 467 suggests logical corruption at Database (JET database engine) level and is exhibited when JET engine touches this location in the database while reporting it as event 447. For specific root causes, one needs to view the application and system log cautiously as these errors can damage your data badly.
Following suggestions can help you isolate the depicted problem:
1. If corruption is limited to index leaf pages and not with the database pages, running Eseutil /d (offline defragmentation) alone can perform Exchange Server Repair.
2. In critical problems, you may need to use ExMerge utility to move the mailboxes to a new, blank Information Store.
3. The Exchange Server might be affected from page or database level corruption together with index page corruption. In such cases, you can execute Eseutil /p and then Isinteg -fix commands as Eseutil /d command may not work. You can further use ExMerge tool to put the database again in use.
4. To avoid data loss problems due to Eseutil /p utility, it is however, recommended to opt for a safe third-party Exchange Repair utility.
The Exchange Repair is a professional utility that repairs corrupted Exchange EDB file and restores the mailboxes in separate *.pst files. The Exchange Server Repair product is easy to use with its self-explanatory interface. Designed for Exchange Server 5.5, 2000, 2003, and 2007, the tool is also competent to recover deleted mailboxes.