I set Windows 7 to turn off hard disks after 20 minutes of nonuse, which it does a really good job at – it seems to turn off individual hard disks that have been idle for 20 minutes exactly. When I access a drive that I haven’t used in 20 minutes, I can hear it firing up and it takes a couple of seconds to access it.
Now Windows is turning off and turning on my hard disks several times a day.
Can this on/offing be bad for the drives? The case is small and I’m trying to protect the drives from overheating really (they get VERY hot!).
Edit: The accepted answer doesn’t mention this explicitly, but from Minimizing hard disk drive failure
Power cycling control
Shutting down and rebooting a computer or resuming it from hibernation cycles the power to the drives in the computer. The spin-up operation performed by a drive after a power cycle is believed to place more stress on the drive than running the drive continuously for a long period of time.
Based on professional experience of system administrators, it is believed that there is a direct relationship between the number of power cycles of a computer and the probability of failure of its drives**. In other words, a computer with a high uptime may have a lower probability of drive failure than one that has its power cycled routinely.
** Attribute #4 of S.M.A.R.T. is Start/Stop Count, which seems to indicate that start/stop count DOES play a role in disk fitness and when to expect a failure.
See also
- Thermal stress relief with Power management
… Energy Star compliance results in an increase in daily power up/down cycles. The consequent thermal shock and mechanical stresses on the system can adversely affect its life…
- Computers and Monitors – When Should I turn them off?
Solution:
Google showed that heat has very little effect on hard drive life expectancy, despite anecdotal claims to the contrary. See this paper. The paper was by far the largest study on the subject. Note, though, that Google keeps their drives running 24/7, so there was no information on specifically whether turning off your hard drives was harmful, only that you don’t need to worry so much about temperature.