[Linux-cluster] Re: More CS4 fencing fun

[Matteo Catanese]

On Tue, 2006-03-07 at 17:04 +0100, Matteo Catanese wrote:



 >Fencing never completes because iLO does not have power.  This an
 >architectural limitation to using iLO (or IPMI, actually) in a cluster
 >environment as the sole fencing method.  Compare to RSA - which can  
have
 >its own external power supply - even though it is an integrated  
solution
 >like iLO.

To me this is a fence_ilo limitation


 >With redundant power supplies, the expectation is that different
 >circuits (or preferably - different power sources entirely) are used,
 >which should make the tested case significantly less likely to occur.

Yes but i want a NSPOF cluster, not a less_likely_SPOF one



 >iLO being unreachable means iLO is unreachable, and assumptions as to
 >why should probably not be limited to lack of power.  Routing  
problems,
 >bad network cable, disconnected cable, and the occasional infinite
 >iLO-DHCP loop will all make iLO unreachable, but in no way confirm  
that
 >the node is dead.

We are always talking about avoiding _single point of failure_, not  
multiple ones.

My ILO_IP_ADDRESSES are static so no infinite dhcp loop

I have bonded (mode 1) heartbeat channel on 2 separate bridged  
switches (powered by 2 different powersupply) so if  one node does  
not reach the other one _AND_ fence_ilo fails, this means (by a SPOF  
point of view) that the other node had power failure.

So please at least for fence_ilo allow some parameter to let fence  
spit out a warning and unlock the cluster service


Matteo