We have three installs of SQL Server 2008 Enterprise and would like to replicate them to a fourth SQL Server 2008 Enterprise server. 2 of the installs are remote (different city) and available via a 10 MB network connection. We would like to sync changes from those databases once a day. 1 of the installs is in the same building and it has access to a fiber connection. We would like to sync changes from this database say every 15 minutes.
The purpose of the 4th server is strictly for staging the three databases, writing a converter, and creating a completely new database schema with populated data. The new database will eventually be shipped to yet another server, so you can think of this specific server as a processing server only.
The databases are not very large nor transaction heavy; about 500 users across all 3 databases. However, they do need to remain semi-responsive 24/7, so we don't want to grind them to a halt with a replication process.
What is the best mechanism for replicating these databases? Is Log Shipping where we should be looking, or the traditional publish-subscribe functionality? Any advice would be greatly appeciated.
Thank you for your help!