Exchange Server Support for Backups and Single Item Recovery

Naturally after understanding the features included in Exchange 2010, a logical follow up question is "Do I still need backups for single item recovery?" The answer depends on your backup requirements and your capacity planning.

Today many customers minimize the deleted item retention window, yet they maintain long backup retention time periods (from 14 days to several months to years).

Let's consider a customer that currently maintains backups for 90 days and only retains deleted items within Exchange for 5 days. This customer is performing backup restores on a weekly basis to recover deleted items for end users. If the customer moved to Exchange 2010 they could move that process into Exchange by simply increasing their mailboxes capacity for dumpster: This post Contain the exchange server support tips to make backups and single Item Recovery.

• Users send/receive 100 messages per work day and have an average message size of 50KB
• Single Item Recovery is enabled and the deleted retention window is configured to be 90 days
• 10% of items are edited
• Mailbox capacity calculations

o 5 work days * 100 emails = 500 emails / week
o For Purges:
+ 500 emails / week * 13 weeks = 6500 emails / retention period
+ 6500 emails * 50KB ? 318MB
o For Versions:
+ 500 emails / week * 13 weeks = 6500 emails / retention period
+ 6500 emails * .1 = 650 emails
+ 650 emails * 50KB ? 32MB
o Total Space Required per mailbox: 350MB

By increasing each mailbox's capacity by a minimum of 350MB, backups are no longer needed for single item recovery. Single item recovery can be maintained and performed within Exchange.

But let's not stop there. What if the requirement is that items must be recoverable for 1 year? Assuming the same assumptions used in the previous example with the exception that deleted item retention is now configured for 365 days, each mailbox needs an additional minimum 1.4GB of space.

Ultimately, if the storage subsystem is planned and designed appropriately and mailbox resiliency features are leveraged, traditional point-in-time backups can be relegated to a disaster recovery mechanism, if they are even needed at all.