At least what you should know about DAG

1. Its a combination of SCR & CCR
2. Its Limited dependancy with WindowsFailoverCluster. DAG uses Windows Failover cluster,heartbeat,& filesharewitness etc.but we neeed not to mangae it from Failover cluster console & its not a full fledged Failover cluster.
3. Active manager ( Primary Active mgrs,Standby Active mgrs) component which runs in each mailbox svr takes care about failover/switch over instead of Exchange cluster resource DLL ( clusres.dll)
4. CCR cannot cooexist with any other Role,Whereas DAG node can cooexist with any other exch role.
5. We need not to deploy DAG intially itself,we can create & add DAG nodes at any point in time.thus its scalable too.

SCHEMA VERSIONS -Operating System & MS Exchange

How do you find Schema Versions -Use dsquery or ADSIEDIT

13 - Windows 2000 Server

30 - Windows Server 2003 RTM, Windows 2003 With Service Pack 1, Windows 2003 With Service Pack 2

Exchange 2010 Features

1. DAG ( Database Availability Group)

2. Outlook WebApp almost like MS Outlook

3. Conversation view,Able to attch mails from OWA itself.

4. Mail Tips

5. No storage groups