Exchange Server database intactness depends on hard disk subsystem. Major database corruption issues can be seen if the hard disk subsystem gets corrupt or suffers from certain issues. In such circumstances, Exchange administrator requires a complete backup to restore the database. But in cases when no suitable backup is available, exchange recovery tools come to rescue.
In order to illustrate the concept, here is a suitable example. Suppose you, as an Exchange Server administrator, attempt to run an online backup for Exchange Server Information Store database. The operation cannot be completed successfully and you observe the below error message showing under the description section of event ID 474.
"The database page read from the file "E:\program files\exchsrvr\mdbdata\priv1.edb" at offset 204275712 (0x000000000c2d0000) for 4096 (0x00001000) bytes failed verification due to a page checksum mismatch. The expected checksum was 303571876 (0x121823a4) and the actual checksum was 303571940 (0x121823e4). The read operation will fail with error -1018 (0xfffffc06). If this condition persists then please restore the database from a previous backup."
Viewing the system log displays a few more events that indicate existing issues related to hard disk, hard disk controller, and I/O operations.
Cause
As per the symptoms, these issues occur due to faulty hardware components, device drivers, or firmware of hard disk subsystem. Error -1018 generally suggests file system level damage and occurs due to checksum errors on database page(s).
Solution
The above problem can be resolved using the steps given below:
-Run the backup procedure on a test storage group, but on different hard disk. This reduces the number of components to deal with.
-Perform hardware diagnostics
-Update the firmware and drivers
-Restore the database from the last available online backup or perform database hard repair using eseutil /p repair command or use a third-party exchange server recovery tool.
The commercial exchange recovery applications guarantee safe database repair unlike Exchange repair mechanism, which tends to delete the data. Moreover, these software are simple to operate.
Stellar Phoenix Mailbox Exchange Recovery is an advanced repair tool for Exchange Server databases that extracts the mailboxes in individual *.pst files. With the capability of recovering deleted mailboxes, this exchange server recovery tool supports MS Exchange Server 2007, 2003, 2000, and 5.5. The software can also recover STM file data in an e-mail body. http://www.stellarinfo.com/edb-exchange-server-recovery.htm
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Tom Patrick a magazine editor currently researching of exchange recovery Article Source: http://EzineArticles.com/?expert=Tom_Patrick |