[sheepdog-users] is --nohalt dangerous?

[Dietmar Maurer]

> But which is the best value for cluster to switch to halt state?
> 
> current_vnode_info->nr_zones <= (sys->nr_copies/2)

This is a simple 'quorum' formula.

> means if we have 2 copies, and one node fails will switch the cluster to halt,
> probably some people don't want to see it. 

Yes, maybe. But as you pointed out, this is dangerous and you can lose data.

> Some people might be pleased to
> run the cluster, even there is only one node left.

OK, so maybe the 2 node is a special case. What about:

		if ((sys->nr_copies > 2) && 
		    (current_vnode_info->nr_zones <= (sys->nr_copies/2)))
			sys_stat_set(SD_STATUS_HALT);

- Dietmar