Write-back cache is a caching technique in which changes to the data in cache are not copied to cache source until extremely necessary. It is applicable on various servers including Microsoft Exchange Server systems.

Write-back caching method results in better performance then other caching techniques such as write-through caching as it minimizes the amount of write processes to the main memory. With performance improvement, it comes with some risks of EDB (Exchange Database) corruption.

The Technical side

When you run unprotected write-back caching against log drive, you may encounter the critical situations of logical corruption. Unprotected write-back caching is the caching where your data may lose if power supply is interrupted.

When write operation to log drive is complete, ESE (Extensible Storage Engine) consigns the transaction and creates the data durable on disk. Durable updates continues even if the server immediately stops responding after the transaction is committed.

After successful completion of write operation to log drive, ESE is free to flush corresponding page to database disk. If data was not written to drive, the same issue takes place and recovery process could not restore the database to working or undamaged state. Thus the EDB file remains damaged.

Resolution

There are two possible solutions of this problem. The first one is helpful to prevent such situations from occurring in future and the second one is to recover database if the corruption has already taken place.

1. You must ensure that data in cache is properly protected with battery backup, error checking, sound operational procedures and error correction.
2. Use Exchange Server Recovery software to repair and restore the corrupted EDB file. Exchange Server Repair software are applicable in most of the situations.

Exchange Server Recovery software are powerful third party utilities that are specifically designed to scan the damaged EDB files and extract data from them. Exchange Server Repair software is designed to be user friendly and its functionality is largely automated.

Stellar Phoenix Mailbox Exchange Recovery is the most comprehensive Exchange Server Repair software that is capable of restoring your corrupted EDB file in almost all logical corruption cases. It supports Microsoft Exchange Server 2003, 2000 and 5.5. Phoenix Exchange Server Recovery is compatible with Windows XP, 2003 and 2000.

For more information, visit: http://www.ms-exchange-server-recovery.com/