Live and backup servers with same node ID

[lqybill]

Hello guys,

    I'm trying to setup a live-backup (replication HA mode) group, with 1 server each. I followed the tutorial and everything works just fine. However I'm stuck when I tried to simulate a scenario where the connection between two servers is lost by putting the live server in background (Ctrl+Z). Once the backup server detected the connection failure and thus became "live" after the timeout, I resumed the former live server, you can see those two run concurrently with the same node ID. Is this normal or am I missing any necessary configuration?

    Thanks in advance!

   

[jbertram]

I don't think Ctrl+Z adequately simulates a network failure.  I recommend you try something else.

[lqybill]

If so, is HornetQ capable of resolving such kind of split-brain problem?

[ataylor]

firstly you are using replication but the servers are sharing the same journal, this is why you see them using the same node id.

secondly, for any system to handle split brain you either need a single reliable source to control it or a quorum, HornetQ uses a quorum to do this. How well it handles it depends on you intranet infrastructure and the number of servers, 1 live/backup pair certainly wont work.

when you test it you also need to configure TTL etc to manage any network outages you have.