I was asked a question regarding DAG
as how to implement 6000 mailboxes in DAG in 3 different places of one organization which has offices in Chicago, new York and china. all 6000 mailboxes will be talking to each other?
my answer was like this which was rejected
1) to create 3 different AD sites.
2) create 6000 mailboxes in one mailbox server having mailbox database as db1 as active
create passive mailbox database -Chicago
3) do same for newyork
4) do same for china
5) create one lagged copy of database in each center
after this I couldn't answer