We run exchange 2010 RTM over two servers one being the hub/CAS and the other being a mailbox server.
I would like to introduce another mailbox server however install 2010 sp3 on it.
I realise in best practices I should have all servers on same SP and probably upgrade my CAS/HUB server to sp3 first but I am sure i can introduce another mailbox server without doing this first.
My plan was simple in that I would extend the schema in prep for SP3 and then add the new mailbox server into the existing environment and move mailboxes from the existing RTM server to the sp3 one, once done this will remove my pain of growing DB and no space.
I’m sure i have worked in mixed environments before but wondered if anyone could say yes or no to this ?
You will need to upgrade your CAS/HUB server to SP3 before proceeding. Not doing so will cause issues with OWA/Outlook connections as some of the components are updated. Your CAS server needs to be on the latest SP before proceeding. It will just make the mailbox moves more seamless to your users.