[LUNI] Failover script?

[Richard Reina]

1) what failure scenarios matter in this instance.  For example, does 
the network topology allow for some machines to connect to DB but not 
others (i.e. lose one switch and half servers on that lose 
connectivity).  Is it just hard down? Are there cron jobs that run on 
the DB server that need to be stopped (do data updates that could cause 
inconsistency if other became master). etc. etc.



All clients via an API connect directly to the master for DB queries.  These a switch which connects all the machnes.   No crons on the DB server that need to be stopped.

>2) What is the fail-over demand? Real-time, automated, manual 
>intervention, transaction-loss-less?  Its worth just describing what 
>your minimum threshold is there.

Automated I think would be best.  Only a few users. 

>3) What is the process for going back to other DB?  What happens to 
>data?  Do you switch replication direction and keep secondary as >master 
>until next failure?

I would probably -- on the weekend when the network can be taken down -- make it the master again and then make it another slave when I do the next server upgrade.

Maybe heartbeat is the best solution.  That's what I would like to figure out before I implement a solution.

Thanks for the replies thus far.

Richard