So we know WHAT and we know WHY.
Let’s cover CLEVER.
Because the cluster is essentially running as a shipping server and a receiving server, there is no clever gadgetary in between. This not only allows the servers to be in separate data centres but also means that the performance hit of CCR is practically non existent on the hardware.
Obviously, because you are replaying every single transaction (and that therefore includes internal traffic and housekeeping as well as inbound and outbound traffic), you need to look at bandwidth between the servers.
If your existing Internet connectivity is running at 30% with your inbound and outbound email, you will double that usage figure just shipping that traffic over to your passive node. Add internal emails and mailbox level changes and pretty soon you will hit a bottleneck if you are shipping off site.
Failover
If you fail the nodes over, the active node becomes the passive node and vice versa. Yes, obviously! The transaction logs shipping completes and the process reverses AUTOMATICALLY so that the new active node ships its logs back to the old active node without admin intervention. As long as the firewalls in between allow the communication is both directions, it should all be seamless. Failover would typically take less than 5 minutes and so for testing purposes would be done as scheduled maintenance!
2 comments:
So could you potentially load balance as well - splitting users between servers and having the CCR configuration between the 2 servers? Or would this just double you bandwidth again? Merry Xmas by the way
Think about it...
Server 1 is CCR'd to Server 2.
Marketing are on Server 1.
Server 2 is CCR'd to Server 1. Accounts are on Server 2.
The witness server is telling the Exchange environment which is the live server...erm, well that's both of them.
No, you'd have all users homed on Server 1 and your CCR box would be Server 2. The witness knows that Server 1 is your live box and when it fails, will flick the switch and Server 2 becomes the live box.
Happy Christmeas to you too.
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