I am running a private network with two ethereum nodes, where one is mining and other one is not. it starts fine, with both nodes having same number of blocks, but after running for about maybe few hours, things are not syncing.
As you can see that the non-mining node had stopped syncing. I have been noticing this problem for a long time.
After restarting the nodes, non-mining node does get synced up. Let's see how long does this stay this way. Though, after using node management APIs I was able to see what might have been doing on - The non-mining node had one peer (and it was itself - doesn't make sense). Here is working peers setting, which makes sense -