Benchmarking set up over HDD+SSD combination? I have a Linux system set up (Arch) on an HDD. I have been trying to benchmark some of my queries and found some disk IO bottleneck, and thus opted to move the entire PostgreSQL database from the HDD to my SSD.

I could notice a difference, however, I can't help but wonder if my set up is still imposing some limitations: I have my Linux OS, testing scripts and interface (psql) on an HDD, and my database server is on an SSD. Can I expect much better results if I move literally everything to SSD? 

I am not so familiar with how the OS/DBMS interaction is working...

If it helps, the SSD is being exclusively used for the DBMS. And my data size fits comfortably over my RAM and SSD.
For database performance it doesn't matter much on what storage device the operating system or the software is installed. What matters is the database storage and the amount of RAM.

When fixing database performance problems, the first thing to try is to improve the query performance and resource usage.