Difference between Exchange Databases Physical and Logical Corruption

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Physical corruption – when the database from an ESE structure is no longer valid in some way

Logical corruption – when the data within the database is no longer valid, but the structure from an ESE perspective is valid

 

Physical corruption cannot replicate. It’s simply not possible with Exchange replication process. Exchange performs a multi-step process to validate the healthiness of the log file prior to replay on the passive copies (in fact Exchange even validates a log file after it is closed on the source now in SP1).

 

 

Logical corruption can replicate. So how can do you deal with logical corruption?

· You can move the mailbox, thereby deleting the bad data. Useful, especially when logical corruption occurred outside the backup retention window.

· You can use single item recovery and restore the original item. Useful when editing message caused corruption (client app caused corruption scenario).

· You can use the Calendar Repair Assistant to detect and correct inconsistencies that occur for single and recurring meeting items for mailboxes homed on that Mailbox server so that recipients won't miss meeting announcements or have unreliable meeting information.

· You can use New-MailboxRepairRequest which can address corruptions with search folders, item counts, folder views, and parent/child folder issues.

· You can maintain an Exchange backup (VSS backup or lagged copy if backup retention window is between 0 and 14 days).