What's the effect of standby (spindown) mode on modern hard drives?

I just assembled a new Linux file server with several Samsung HD103UJ 1TB hard drives and I am currently optimizing it.

The question I can't find an answer to is: is it reasonable to set a spindown timeout (with hdparm -S) for the drives? Can the spindown/spinup be harmful to the disk in the long run?

My previous file server did not have this timeout and the hard drives have been operational for 3+ years with no problems (always on) so I am not sure if I need this optimization at all.

What are your thoughts on this?

Thanks!

I'm by no means expert on disk drive physics, but I see disproportionally many hard drives fail soon after the spinup. Probably the temperature change just does not serve them well. I would say: let them spin forever.

Is there any hard data on this phenomenon?

Frankly, this issue reminds me of my grandmother flipping out about using the phone in a lightning storm.

You always hear anecdotal accounts about how you need to keep drives spinning, but I've never seen anything based on verifiable data. I've run into a few instances where drives didn't come back after being powered down, but I've also run into many instances where everything came up just peachy.

** 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.

It's going to depend on the workload. You probably only want to spin the drive down, if it's not likely to be used for quite a while...