if CAS and DAGs are on different servers, and only CAS in the primary site are down but databases are up, client in primary site will be able to connect? where CAS working from secondary site and active mailbox copy in primary site.

My understanding is CAS is proxy from CAS to CAS, in case only CAS is down, if a user will try to connect to his mailbox through CAS is secondary site and mailbox is primary site will not work

Mailbox should also need to be moved into secondary site dag member,

Is this understanding co

Hi SMF,

Thank you for your question.

If the CAs down and database are up, the client will connect to second CAS server. the CAS server which is in second site will connect to mailbox where is in primary site instead of second site. So mailbox didnt move into second site.

Mailbox will be moved to second site when DAG member is down in primary site.

If there are any questions regarding this issue, please be free to let me know. 

Best Regard,

Jim

As Jim states, the CAS role will connect to a Mailbox server in any site to provide connectivity to the end user, providing it can get to it.

Oliver