Is this a frequent thing? I mean, how many of you place parts of websites on separate and distinct webhoster not only to save on bandwidth but also to increase redundancy. Again is this a good thing to do or not.

You can't do redundancy that way. If one server is down, the part of the site hosted by that server will be inaccessible, regardless of availability of your other servers. You need to replicate your content across your servers, but that also requires you manage your DNS servers in some way that it guides your visitor to 'correct' servers. It won't be an easy and cheap solution.

I guess one would look into solutions for load balancing, which bring at the same time the redundancy, of course that would mean several servers but still all of them in the same datacenter, so it's not safe against NOC failure...

Otherwise some other sort of tricky stuff is needed, like what Akamai does for its clients...

Interesting question. That's one point why I keep having an eye on JSP/Servlet, this Java server stuff is supposed to allow for load balancing and hence redundancy quite easily :)

Astra4. One can always do load balancing whether he is using JSP or not. Or is there something unique to JSP about load balancing and not available to other technologies?

If your running the DNS you could set a low ttl on the webhost record. Run a script which will check to see your sites down, if it is, change the host record to another site. You'll be putting a decent amount of traffic at your DNS though.

I've never heard of this bieng done but I don't see why it wouldn't work. It's the same thing dynamic DNS services do for the most part.

Originally posted by jstout
If your running the DNS you could set a low ttl on the webhost record. Run a script which will check to see your sites down, if it is, change the host record to another site. You'll be putting a decent amount of traffic at your DNS though.

That will work (as well as round robin DNS), but then ... how if your site is generated dynamically with mysql? How do you make your database available on different servers and keeping in mind that these databse copies have to be identical one another? I heard mysql will allow you to have redundant datatabases across several servers, even in different network. Anybody has tried anything like this?

cheers,
:beer:

Originally posted by priyadi
Astra4. One can always do load balancing whether he is using JSP or not. Or is there something unique to JSP about load balancing and not available to other technologies?

I guess you're right ;)

I keep following the news from jBoss.org, jBoss 3.0 comes with support for load balancing and will hopefully provide for session persistence (not implemented yet), but there's only an alpha release so far which means there won't be a stable/production build for another while...

Actually I don't know if Apache has what it takes to assure session persistence when using load balancing, I always thought that this is an "application server" feature and since they are usually expensive I am looking at open source ones, hence jBoss which is JSP/Servlet... :)

Astra4. I think if you store all session information on central database you will achieve session persistence across load balanced web servers, regardless of platform or language used. I guess JBoss requires special modification because it uses its own way of storing session information. It is not as complicated as you think, and not as expensive :).

Hmm, yes, sounds reasonable, database persistence is indeed easier than in-memory session state replication.