[DRBD-user] What happens after both nodes have gone down?

Martin Fick mogulguy at yahoo.com
Fri Feb 13 02:02:17 CET 2009

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


I have a question about DRBD that has been bugging me for a while, perhaps someone can help me? :)

I am concerned about the "cluster boot" phase of drbd.  What I mean is, I am concerned about how to deal with both nodes in a cluster going down (not necc. synchronously) and what happens after one or both of them comes back up.  

It seems like most heartbeat/drbd combinations expect both nodes to come up or they will (should?) not proceed to allow a node to become primary, is this correct?

In other words, suppose:

1) node A is primary and node B goes down.  Node A stays primary and continues to process writes.  Eventually, node A then also goes down.


2A) node A comes backup while B is still down.  Node A will wait until it communicates with node B and will not get promoted.  When node B comes up, either node may become primary.  Is this correct?


2B) node B comes backup while A is still down.  Node B will wai until it communicates with node A and will not get promoted.  When node A comes up, either node may become primary.  Is this correct?


dopd seems like a neat feature to outdate a peer when communication is lost, but it will not come into play in these situations, will it?

Thanks,


-Martin




      



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