MySQL Replication

[radalin]

Hi,
I'm curious about how the replication thing works with MySQL. I found lot's of Master-Multi Slave models which are quite for most of the databases about replication but what about a Multi Master - Multi Slave model? I have searched a little bit and found a solution as MySQL Cluster. But it's not totally recommended to use with an internet connection but only use in a LAN. Thing is it possible or recommended to use such a cluster system in a network which nodes are connected not via cable but via internet!
What about other possibilities for such a model? I have also read something about a main server and then lots of slaves which sends daha to the main server to avoid increment value problems, if we have N nodes then the increase rate of the auto_increment is N. But the problem is the last value of auto_increment is 65,000 or something like that (correct me if I'm wrong I'm not that sure) while PgSQL's auto_increment(serial as they named...) value is something with 15 digit or something. 65,000 is quite a number if you have one server. But if you have N servers then this value becomes very low. And also the N increment solution is not that good if you intend to add one more node then you have to re-build all your architecture (yeah we can start from N+1 or something but what about we reach the end of that too...)
A little scenario to explain what I mean more clealy. Let's we have two servers one at USA and other at UK. they are both masters and both slaves. While someone enters a data to USA, UK becomes the slave and USA master and vice versa. This can be done by an asynchronus solution I think (which it's not that important as asynchronus or synchronus in my case...) can there be a data integrity problem any time. I'm sure that it can, but how often, what are possible problems that can occur (hardware errors, or server lockdowns are not the case, I just ask problems about the replication and mysql problems.)
And also do you know anything about other databases such as PostreSQL,Oracle,MSSQL or DB2.

It's not very easy to answer this I think, but your answer is welcome. Also I appreciate some articles and reviews about this subject too.

Thank you for your time.

[fenway]

Having never used replication, I can't really be of much use... but the auto_increment will go as high as the the maximum value of the column, which for a BIGINT UNSIGNED column is 2 x (2^32) = 8'589'934'592.

[radalin]

Honestly I was expecting a good reply from you :)

Well but it's very good to learn that big int can go that high. Now I can also search mysql too for my research.

Thanks :)