I am currently setting up a cluster made up of boards from old laptops. Long term file storage for the cluster will be accessed through a file server on the local network, so each board in the cluster requires a small attached hard drive just for temporary local files and the operating system (ubuntu). That being said, I am looking for some sort of mini hard drive which is cost effective and trustworthy. Since the boards are from laptops they just have one SATA connector for a HDD. I was even thinking of using very small flash drives for the OS, but this seems inefficient given most of the laptop boards support only USB 2 at best.
What hard drive models would you recommend given this criteria? If you've done something similar, what worked best for you?