[no subject]

The "shoot in the head" method is good until there is a problem with the
B machine. HA only work as long as there is failover capability.
Headshot HA requires a fast reboot process with a good amount of logic
in the HA startup. 

Note also, HA really only works best as a read-only service. Unless all
nodes are active and there is a separate synch process from the writes.

On Tue, 2004-09-14 at 13:42, Stephan Uphoff wrote:
> Read up on split-brain syndrome.
> This happens when both servers think that the other one is dead
> and access a shared storage device.
> This can destroy a filesystem really, really fast.
> Depending on your heartbeat solution this can happen as easily as
> a server being to busy/low on memory,.. to send a heartbeat signal.
> With a bad heartbeat solution your redundant server setup can 
> be less reliable then a single server.
> A good solution is the "shoot them in the head" approach:
> If server B thinks server A is dead -> B cuts the power to A.
> Now B can be sure that A is dead ;-)
> 
> 
> On Tue, 2004-09-14 at 08:50, Kevin O'Neill Stoll wrote:
> > Hi all,
> > 
> > I have been doing some research about either:
> > a failover pair of fileservers, possibly load-balanced
> > across the pair
> > or
> > a high-availability load-balanced cluster of file servers
> > 
> > I just wanted to know if anyone was already working with a
> > particular setup or product that they have had success
> > with. I have been doing all the basic reading / research
> > that I can find via google, tldp, and linux-ha.org.
> > 
> > I have already found OpenGFS, a Networked Raid 1 type
> > setup, and supposedly RedHat's cluster management package
> > has a solution available.
> > 
> > Any thoughts would be greatly appreciated.
> > 
> > =====
> > Kevin Stoll
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