On 20 jul 2011, at 16:16, "Dinse, Gregg (NIH/NIEHS) [E]" <[email protected]>
wrote:
> Hi John,
>
> Thank you for the idea that the noise may be related to the disk(s) spinning
> down at the default time (10 minutes). This may be exactly what is causing
> the sounds that I hear. I will check into it.
>
> Until recently, I believe that the check box in the Energy Saver panel for
> "put the hard disk(s) to sleep when possible" was NOT checked. About a week
> or two ago, which is about when I started hearing these noises, the sysadmin
> folks made some energy saving changes to all systems. I forgot about this,
> but now I see that the box is checked, so that may explain the noises that I
> hear. To test this, I will uncheck the box for a few days and see if I still
> hear anything.
>
> By the way, for energy saving reasons, I can see why it might be a good idea
> to put the disks to sleep. Overall, is this good or bad for the health of
> the disks? Does frequent sleeping and waking put added strain on the disks,
> so that it is better to let them always run, or is there really no
> significant disadvantage to putting the disks to sleep?
>
The short answer to this is I don't know if it is tearing a bit more or not on
the disk, regarding mechanical tear and wear. This would require a rather
lengthy test with several disks of different kind to get an answer about disk's
in general, or a test with your particular disk type to answer it with only
your disk in mind.
Since it is a bit related I do know of Google tests that came up with the
rather surprising result that disk's dedicated to 24/7 workloads did not seem
to be of any better qaulity than other disk drives!
In lack of any knowledge about which aproach is best for longest lasting period
without a failure you really should use the strength of RAID. If the data or
uptime is important RAID1 is going to almost eliminate the risc if you act on a
single disk failure and not let it continue for any longer period of time on
one disk only. For the ones that don't enjoy to be nervous, a mirrored pair
with a spare disk connected would keep you on a pretty safe ground here. I
don't know anything that is near RAID in terms of lowering the risc of disk
failures causing failure to a system, apart from turning the machine off
entirely?
// John
_______________________________________________
MacOSX-talk mailing list
[email protected]
http://www.omnigroup.com/mailman/listinfo/macosx-talk
