In designing an archival system, we're trying to find data on when it pays to power or spin the drives down versus keeping them running. Is there a difference between spinning up the drives from sleep and from a reboot? Leaving out the cost imposed on the (separate) operating system drive. Temperature obviously matters -- a linear approximation might look like this, Lifetime = 60 - 12 [(t-40)/2.5] where 60 is the average maximum lifetime, achieved at 40 degrees C and below, and lifetime decreases by a year for every 2.5 degree rise in temperature. Does anyone have an actual formula? To keep it simple, let's assume we keep temperature at or below what is required to reach average maximum lifetime. What is the cost of spinning up the drives in the currency of lifetime months? My guess would be that the cost is tiny -- in the order of minutes. Or are different components stressed in a running drive versus one that is spinning up, so it's not possible to translate the cost of one into the currency of the other? Finally, is there passive decay of drive components in storage? Dave - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html