Can I use Amazon ELB for my RDS instance for load balancing?

Question

I have two questions:

1. Can I use ELB on my RDS instance for load balancing?
2. Can I install multiple servers on EC2 instance and run single ELB instance for all servers?

Answer 1

1-If you mean having only one RDS instance, there is no point in load balancing requests in front of it. If you mean having more than one RDS instance, it does not make much sense as well to load balance requests, because your database servers will most likely have different data in a given point of time. The only exception that I can see to this rule is if you have read-only RDS instances. In this case, you can probably benefit of having ELB(s) in front of them. If your application is write-intensive, you should stick with a larger RDS instance or move to a noSQL database. Don't try to load balance requests to a read/write DMBS, because you will have to deal with synchronization and a lot of other (non-trivial) aspects by yourself.

2-Yes, this is totally feasible. For web servers, of course. Not for DBMSs in general.