load balancing question

[biry]

hi i have a question regarding a server set up, i have 2 banks of servers. Each bank contains a web server, a db server, and an index server. Now the two banks are identical in every way.

Now i want to have a fail over situation with a load balancing switch, having each web server listen on port 80.

my question is... should i have only 1 db server and 1 index server? what happens if a web form updates a database, and only one gets the information, or the index servers are parsing the net at the same time and bandwidth is eaten up cause of it? I'm not sure how to set up the web and db and index servers so that they always have the same info for a fail over senerio. I hope i explained myself clearly, if not please let me know.

B

 

[joseph1475]

What I would do is, load balance the web servers, Cluster DB servers. I've not worked with index servers so I am not sure how you can load balance it.

 

[biry]

thanks joseph1475, any other ideas out there...

 

[biry]

any heavy duty server users here?

 

[biry]

a last call for your opinion to the original question

 

[NickFerrar]

Joseph is right in how you should do it. Load balancing shouldn't be used for redundancy of stateful applications (i.e. stuff that changes like databases). Depending on what the whole environment was doing you might be able to get away with using some synchronisation software (I think Robocopy can do this sort of thing) or regular databased exports and then manually fail over to the second DB server if the primary server fails - but the chances of that working are slim to none if the DB server is frequently updated.

 

[biry]

i'm looking into robocopy as well as xxcopy, thanks. so is it best to setup the two web servers with loadbalancing switch, cluser the db and use robocopy on them and ONLY USE ONE INDEX SERVER ?

thanks

 

[NickFerrar]

I don't know what a separate index server does sorry, indexing has always been done as part of the database in all installs I've done.

Personally I'd just NLB (Windows built-in Network Load Balancing) the front end web servers (no need to use a load balancing device unless a high volume of traffic is involved. And then run the DB backend as a Windows cluster (with indexing on the same server as each DB if possible), whether you can run it as an active/active or active/passive cluster depends a lot on the app itself and the hardware involved.