I'm considering running chrony in a setup where it has access to a pair of local time servers that I would prefer it use for synchronization.
But, I recognize that with only 2 sources, its difficult to guess which one of them is lying if one of them goes crazy for some reason.
So, in addition, I'd like to specify additional remote servers to be used to help detect falsetickers and as a fallback if both of the local servers are not available.
But, in general, I would prefer if the remote sources were not combined to discipline the clock, as there is more uncertainty in the time they are providing (by virtue of being farther away).
I went reading through `SRC_SelectSource' to see if I could figure out how to get what I wanted, but its a big function and I'm not entirely sure I understand it.
I think I can get what I wan't with something like:
server local1 prefer
server local2 prefer
server remote1
server remote2
server remote3
server remote4
combinelimit N
Which, I think says:
Consider all the `server' lines for the purposes of determining the time and figuring out falsetickers. But, when choosing the source to select, prefer those marked with prefer, in order.
In addition, don't combine sources whose root_distance is more than N times that of the selected source (I'd have to figure out the right value of N for the local and remote servers in question).
Does that sound like it might get what I want? Are there other config options I should be looking at?