Database Confirmation (Verification, emancipation, something like that..)

[squiggerz]

So I'm building my own CMS, mainly PHP, some js/ajax and all backed by a mySQL db.

 

I want to have 3 separate databases that will be added to, deleted from, updated all concurrently, so to put it better, I'll have three identical databases all the time. The idea is if one goes down, one of the other two will pick up the slack.. somehow.

 

I have two questions, and I don't necessarily need a definite answer, just a push in the right direction. I'm not sure if I'm just using the wrong search engine terminology or what, but I've done quite a bit of research and I can't seem to get on the right track. Anyway:

 

1. Is there any way I can set up these three databases to work the way I want to? That is to say if someone accesses a page that gets data from the db, that if the first db on one server is unavailable, it would be able to pull from another in a fluid fashion?

 

2. If I have these three dbs, and I make changes to them all simultaneously, is there any sort of verification that I can set up that will make sure all of them get changed so the data stays concurrent?

 

 

Like I said, even a gentle shove in the right direction would be appreciated, I don't care to read and learn like everybody else, but I'm spinning my wheels here..

 

Thanks, Sq

[drisate]

I just really don't get why you use 3 times the same db ... That would be a good enoug reason for me to neveruse your cms ...imagine ... 3 times the same stuff for 65 000 members for an avrage website after 6 month thats crazy. Explain me better why you do that, maby we can figure a better way lol

[squiggerz]

Well it's not really going to be geared towards mainstream cms type usage, it's for a local advertising/directory network, it will maintain customer ads/banners as well as phone numbers and addresses on about 12 different sites. Think of a CMS that manages the data for http://www.yellowpages.com

 

But anyway, the 3 database situation is meant to ensure that anytime someone accesses one of the 12 sites that the database is linked to, they will be able to access the information they are looking for.

 

I know being able to ensure 100% availability is almost completely impossible, but I'm trying to cover as many bases as possible.

 

The information in the database is minimal, mostly containing paths and small amounts of code for each individual ad/banner/info, so the 3 database set up seemed feasible from that standpoint.

 

Even just a second database would probably work, the 3 database idea was sent down from above me, so I really don't have a whole lot of pull to change that unless I can find a much better idea.

 

I hope this at least kind of explains what I'm trying to do, happy to hear any ideas you might have, it means a lot