I have 3 linux servers running the following:

Server 1:
RHEL
Apache

Server 2:
RHEL
MySQL

Server 3:
RHEL
File Storage

I need to duplicate this same configuration at another location in case of an outage.

So the setup needs to look the same way, like this:

Location A

Server 1:
RHEL
Apache

Server 2:
RHEL
MySQL

Server 3:
RHEL
File Storage


Location B

Server 1:
RHEL
Apache

Server 2:
RHEL
MySQL

Server 3:
RHEL
File Storage



Any changes made on location A need to be reflected on location B. OS changes can be done manually at both locations. File storage information can be transfer from location A to location B using a cron job. Data in mysql needs to be replicated from location A to location B automatically.

Questions:

1. What will be the best way to replicate mysql information from location A to location B thru a VPN?

2. In case of an outage if DNS records need to be changed to point to the IP on location B what will be the quickest way to do this and have also the end user refresh the IP information on their DNS servers?

3. Any other inputs?

Thanks for the assistance,

MySQL Replication.
http://dev.mysql.com/doc/refman/5.0/en/replication.html

If this is the way you want to do this kind of failover then use a very very low TTL on your DNS records so that 3rd party caching nameservers must re-query reasonably often

Data replication is much better handled by DRBD. In your case you shouldn't see any performance problems as you would use Protocol A since Protocol C is not necessary in your case.

If you have a VPN line between the two servers/sites you should consider using Pacemaker for your High Availability needs as it will handle your fail-over automatically.

Thank you very much for the information.