I need tracking for about 1 week to 1 month without losing any performance to evaluate databases for replatforming. I want to set up servers with heavier transaction volumes balanced across 2-3 servers. I am new to the datacenter environment (previously a developer at another shop) and would like some advice on how transaction volumes can be documented.
Use System Monitor to track counters. SQL Server has a number of them and you can grab user counts, transactions/sec, and anything else that might impact your decision.
It's really load you're documenting, not just transactions.