Using ISINTEG for Exchange DB testing
ISINTEG is used to check and fix the integrity of the Information Store DB in Exchange. It is the only tool that understands the Exchange DB at a mail and object level rather than at the pages/table level which ESEUTIL operates at.
Given that this tool requires the DB to be dismounted you won't be running it all the time. Really you only need to run it when you are having specific problems perhaps with corrupted items in a mailbox for example.
The follows links are a great source of help if you are planning to run this tool on your DB.
http://support.microsoft.com/kb/301460/
http://www.msexchange.org/tutorials/Exchange-ISINTEG-ESEUTIL.html
http://support.microsoft.com/kb/182081
Hope these help
Cheers
Nathan