Why should you backup an Exchange 2010 DAG implementation with DPM?
What should you be thinking about before you make a final decision?
What is the way out of this conundrum?
If you want to deploy Exchange 2010 with JBOD, it is recommended that you should deploy with at least three copies. In addition to this, if you want to also use the DAG copies for Point In Time (PIT) recovery, then you will need a server to host the lagged copy of the DB. Lagged copies are a means to safeguard against store/logical corruption events (and possibly accidental mailbox deletions). If you are going to distribute the lagged copies among your primary severs, then you will need at least two lagged copies. If you are going to use dedicated servers with lagged copies with JBOD, for better reliability you are well advised to deploy enough servers to house two lagged copies; otherwise you could deploy dedicated lagged copy servers with RAID and thus only have one lagged copy per database.