[sheepdog-users] Force cluster to start with a missing node

[Liu Yuan]

On 12/21/2012 07:31 PM, Valerio Pachera wrote:
> Think of this situation:
> we stop the cluster for do some maintenance.
> We find out that a node has hardware problems and we do not want (or
> can't) use it again.
> We are also unlucky (and not provident) and have no server to substitute.
> 
> The cluster will refuse to start with a missing node.
> Is it possible to force it to start?
> 

Well, in this situation, you can at first place run format the cluster as
 $ collie cluster format -m unsafe # or
 $ collie cluster format -m quorum


unsafe mode means cluster will continue even only one node is alive
quorum mode means that cluster will continue
 - if nr(alive nodes) > nr_copy/ 2

For e.g, in quorum node with 3 nodes(A,B,C) formated and copies = 3.
Then if one of the node fails, cluster will still continue because 2 >
(3/2) and if 2 nodes fail, the cluster will halt.

Thanks,
Yuan