Really? I didn't know that a single machine could act as both a slave and a master for the same DB. Hmmmm.... This opens a whole new world of possibilities. Okay - I can understand the issue for autoincrement columns becoming a problem. UIDs per server would need to be used in that case.
But what happens if there is a break of communication and the same record on both machines is modified? For example, if the sync link is down, and I update record #1 on A, while at the same time, another user is modifying record #1 on server B. When the link comes back online, how will the servers be able to synchronize record #1, or in the case that this is impossible (I can't even imagine how I would do that manually - merge? A overwrite B? B overwrite A?), how does MySQL flag it and let me know that there is a discrepancy in the two DBs? Are there any good whitepapers or docs that I can read about two-way synchronization? Thanks! Eric "John McCaskey" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] Yes, Lets call the two serves A, and B. You set A as the master for B, and you set B as the master for A. In this way you can insert/delete/update on either side and both sides will be kept in sync. If you plan to actively use both at the same time you do need to be weary of some syncronization issues however (for example autoincrement collumns may be unsafe if you are inserting to both at the same time). So the answer to your question is that getting the slave to syncronize back to the master is not a nightmare, because both can be masters and slaves to each other and then this will all be handled automatically as soon as the servers are able to reconnect to each other. John ________________________________ From: news on behalf of Eric B. Sent: Sun 2/29/2004 9:51 PM To: [EMAIL PROTECTED] Subject: Replication / Synchronizing DB across different machines Hi, I'm at the stage where I need to create redundancy in my network / DB server. Am currently using MySQL 4.0.x, and have been trying to figure out how I can safely replicate/synchronize between different machines. I know there is a way to do a Master / Slave replication, but I'm looking more for something that will allow 2 way replication. My problem is that I need to have my DB always available. If my primary server (master) goes down, I need another server (hosted in a different geographical location) to pick up the slack until my primary server comes back alive. If I do a simple master/slave replication, getting the slave to synchronize back to the master once the master comes back alive is a nightmare. MS SQL allows full 2 way synchronization between different servers. Is there anything I can do in MySQL that will produce a similar result? Thanks, Eric -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
