StorSimple's Solution to Ballooning Exchange 2010 Storage

Exchange 2010 has substantially increased storage needs:

• One of the exciting new developments of Exchange 2010 is the introduction of Database Availability Groups (DAGs). DAGs protect Exchange database contents with disk-based database replication. Each Exchange database can have up to 16 replicas, all automatically managed by Exchange. In a typical setup, two to three database copies are sufficient to protect Exchange data. One of the "gotchas" of DAGs is the resulting storage increase. Even with three database replicas, the resulting storage increase can be significant.
• Say, for example, the average mailbox size is 1 gigabyte. Do you plan to implement the new Archive Mailbox features of Exchange 2010? If so, add another 2-3 gigabytes for long-term retention. Do you plan to upload existing PST files into the archive mailbox? If so, add another 1 gigabyte. Do you plan to use Exchange's unified messaging and store voicemail? If so, add another 1 gigabyte. And finally, you need to factor in a 25% storage increase because single instance storage was removed with Exchange 2010. Depending on how you answer these questions, the average mailbox size could increase to 6-8 gigabytes.
• So for a three-copy DAG (two local and one remote for DR), the total storage capacity for the single mailbox increases from 1 gigabyte to 18-24 gigabytes!
• The example we use is hypothetical and obviously an extreme case. But it is clear that depending on how you implement Exchange 2010 archiving, PST management, unified messaging, and DAGs, storage capacity is substantially greater than previous Exchange versions if you implement all the features. Even if you provision Exchange with low-cost SATA drives, the resulting total storage is quite daunting.

This problem has not gone unnoticed. A new startup called StorSimple is developing a storage appliance that bridges local and cloud storage in a seamless manner. If it all works, you could use the StorSimple appliance for Exchange 2010 storage and leverage all the extra capacity required with DAGs with inexpensive cloud storage (you pick the cloud vendor). An interesting idea.

...David Ferris

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