Wednesday, 8 August 2012

Understanding Exchange Storage Group


Understanding Exchange Storage Group



This video will give you the basics of Exchange storage which you need to know before you start creating your Exchange storage groups and databases.

The process of installing Exchange will see to the creation of a default Exchange storage group with a single database.  In addition, a public folder database will also be created if the “free Outlook 2007 clients” option was selected during the installation process.
Examining the Exchange folders from Windows Explorer, it is possible to see the various Exchange storage groups and their respective database, which has an EDB extension. The size of this database increases as email is added, with a size limit of 50 GB for Exchange Standard Edition and no limits for Exchange Enterprise Edition.  The size limitation of the former can be modified through the registry, though it should be noted that a larger database will take longer for recovery in the event of a hard disk crashes, or database corruption.
Also present in the same folder would be files with an LOG extension called transaction logs. When new e-mail enters the server, it goes into the memory and is written to these logs, before being written to the database eventually. Each log is 1 MB in size, and helps provide redundancy for your mail. The current log is e00.log, which will be closed and renamed with a longer name when it reaches the 1MB limit.
The Exchange storage group can handle more than one database, but the logs for these databases will be intertwined within the storage group’s folder with no separation between the two. As such, having several databases within the same storage group may be a negative impact on performance or recoverability at some point. For this reason, Microsoft recommends using one storage group for one database.
Finally, it is recommended that log files and the Exchange database be kept on a separate drive from the one that holds the operating system. An even better option would be to use a RAID 5 storage volume for the Exchange database file and a RAID 1 storage volume for the transaction logs.  This will allow data recovery from the transaction logs should the Exchange storage database fail or become corrupted. These are the best practices for your Exchange storage group.

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