[Linux-cluster] qdisk WITHOUT fencing

[Gordan Bobic]

On 18/06/2010 00:46, Joseph L. Casale wrote:

> You can make use of whatever technologies you want such as iptables, switch
> ports etc in your own script and return a "success" to the fenced so things
> carry on.

Absolutely. Many things can be used to provide reliable fencing.

> I use drbd between my two node w/o a qdisc and have drbd play a role in mitigating
> the issues you describe. My two nodes are also separated by fiber and I
> encountered the same issue where one node might be able to fence the other
> properly.

Sure, DRBD can assume it's primary after a timeout when the peer goes 
away, but the stonith option is there for a reason. Ultimately, when the 
other node re-joins, one DRBD instance will "win", and the other will 
sync to it. If something else was accessing it at the time, it'll have 
the rug pulled out from under it when it's FS consistency suddenly goes 
down the pan.

Gordan