Forum Discussion
Jul 18, 2022
Adding a 3rd device will require additinal self IPs, additional firewall permissions to allow monitoring from the new self IPs to the pool members.
Here is the plan:
Replace machine A by machine C.
Replace machine B by machine D.
Prepare C and D with the network settings (VLAN and Self IPs) of the corresponding machines A and B.
Put C and D in "Forced Offline" mode.
That´s why I prefer to do the following:
- Backup both machines (active [A] and standby [B])
- Put machine B into "Forced Offline" mode and isolate it from the network
- Remove machine B from the sync-failover device group and delete the device trust
- Add machine D (having the network settings of machine B) to your network
- Establish device trust from A to D, add D to the sync failover group, do the initial sync from A to D
- Release D from "Forced Offline" and watch the monitoring results
- If everything becomes "green" on machine D and Self IPs are reachable, trigger a failover
- If everything runs fine through D now, you can apply the same procedure to replace A by C.
I have done this a couple of times with both v14 and 15 and faced no issues so far.