Verify Failing Drives in Linux

I'm a PostgreSQL administrator which is running on CentOS 6. My question is from time to time, I will ask if there's any issues w/ "the database" in regards to CRUD operations are slow. I usually have a few scripts in which I verify no database blocks or read/writes are colliding but I would like to know what should I be checking from an OS level to verify my drives are all running well w/o errors? Are there any tools / scripts I can use to verify my disk health on Linux?