Currently I've got server A and server B running with the following mongod instances:
- mongod server (usually PRIMARY)
- mongod arbiter
- mongod server (usually SECONDARY)
When server A goes down, server B fails to elect itself as primary to take everything over. As such, my entire application goes offline as the database is unavailable.
My question is, without increasing the amount of physical servers, how can I make sure that server B takes over properly when server A goes down?
Would the following be a good idea?
- mongod server 1A
- mongod server 2A
- mongod arbiterA
- mongod server 1B
- mongod server 2B
- mongod arbiterB
Where I have not added an arbiter to B because that would make the total number of servers even. The question is: is this the most efficient way to let server B take over when server A powers off? Or can I remove some servers to save RAM/CPU/HDD?