On Sun, 2006-02-05 at 15:42 -0800, David Liontooth wrote: > 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 I read somewhere, still looking for the link, that the constant on/off of a drive actually decrease's the drives lifespan due to the heating/cooling of the bearings. It was actually determined to be best to leave the drive spinning. Brad Dameron SeaTab Software www.seatab.com - 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
