I setup MySQL one-way replication between the two MySQL servers. That means both DB's are always in sync, with the 2nd (and 3rd...) DB updated from the master. As soon as you add another row into the db only in the secondary db, the replication will stop updating the secondary db. I have two RADIUS Servers (with MySQL on the same server) at different locations, but only allow access (via firewall) to the primary one. If the primary server is down, I would have to open my firewall on the secondary server and the connected devices would use the up-to-date db. When the primary server is back online, the firewall must immediately disable any radius access. You can then setup the secondary DB as the master and primary as the slave, synchonizing all radius entries, switch radius back to the first one and set the replication back to the original state. Most of this could probably fit into a few shell scripts doing the job more automatically. I know that my failover is not automatically, but I have not really found a better way yet with MySQL. Maybe Postgresql has better features. The MySQL replication is so far (over 4 month) very reliable. If both of your MySQL servers are on the same LAN you could also set up 'MySQL Cluster', which would make failovers automatically and there would be no manual intervention required. But apparently you cannot do that with servers connected over the Internet as there is quite a network load. Gunther
-----Original Message----- From: Maqbool Hashim Sent: Friday, March 17, 2006 1:38 PM I have two radius servers one primary and one backup one, on different ip addresses. They both have a mysql backend which runs on the same physical machine. I need the sql database and radius configuration files to be synchronised periodically (probably every 24hours). I guess this is a common setup, so I'd appreciate some ideas as to the best way to achieve this?