On Jun 12, 2007, at 10:20 AM, Jeff Genender wrote:
Dain Sundstrom wrote:
If the version number isn't shared amongst all servers, then I would
think the version number will need to contain a server identifier to
avoid the case where the client fails over and old (dead) server
happened to be on the same version as the new server.
Why would this matter? If the client knows its failing over, it
signals
this and gets the whole list and the updated version number from the
server. Is a server identifier really necessary?
Well, that would be another way to implement it. I was assuming that
when there is a fail over the client simply begins to talk to the new
server. If you design it to have a new custom messages in the
protocol, the sky's the limit. If you want to stick the initial
protocol messages, I don't believe there is a way to signal a
"failing over".
The clustering systems I have seen tend to have a global cluster
version number as a side effect of the cluster communication
protocol, so people using these tend to simply send them to the
client. Having no idea what the cluster protocol looks like, I guess
it was a bad assumption you would have one.
-dain
