I recently completed a migration from Exchange 2007 (with Windows 2008 SP2 OS - physical server) to Exchange 2013 (with Windows 2012 sp2 OS setup on ESX managed by vcenter and netapps FAS storage using ISCSI).
Also, I had another temporary Exchange 2013 (with Win 2012) server that was setup by previous IT admin and had 10 mailboxes migrated from 2007 and it was using different certificate and different CAS name. Now I have moved mailboxes from both server.
After decommissioning both the old exchange 2007 and 2013 I am planning to unjoin and join them back to domain. I was planning to use Windows 2008 r2 as witness server and Win 2012 with exchange 2013 as DAG member.
Is it possible to use Windows 2008 r2 as witness server with DAB members hosting Exchange 2013 in Win 2012 servers?
My single exchange server host both mailbox and front end role? Would it be possible to create DAG out of server hosting all server role? If so does secondary member only needs mail server role or all role as primary DAG member.
Is there a detail references of DAG setup? Both video and text blog would be appreciated.