Clever repeatable benchmarking and bottleneck detection test bench - PostgreSQL
While I can't speak to measuring specific metrics like CPU, storage throughput, etc. in your environment, I have found HammerDB to be a good tool for running a good, standardized benchmark against your databases.  This tool runs an unofficial TPC-C benchmark against your database. You can configure for concurrent user connections and workloads.  Using this conjunction with other metric tracking will help you evaluate your system for bottlenecks in an application agnostic manner.

As a note, HammerDB supports the following platforms at this time:


Oracle
SQL Server
MySQL
PostgreSQL
Redis