Comment 109 for bug 59695
Revision history for this message
| Blue (vali-dragnuta) wrote Re: default value in power.sh potentially kills laptop disks | #109 |
© 2004
Canonical Ltd.
•
Terms of use
•
Data privacy
•
Contact Launchpad Support
•
Blog
•
Careers
•
System status
•
73416ba
(Get the code!)
Gilles,
I think the root of the both evils is common :)
On a desktop computer, spinning down and then spinning up the hard disk produced the same annoying "clank". If I had a newer and quieter hard drive on that machine
I could have missed this problem ... (or at least realize it only later by the spinup delay).Because the noise I found it just about an hour after installing the new release on this machine :)
I myself solved the problem by setting hdparm.conf and disabling apmd and acpid (unneeded on that machine). So I'm not affected by this problem any more myself.
Now, we must make the difference between the following parameters :
1.Start/Stop Count and
2.Load/Unload Cycle Count
The first counts how many times the hard drive entered sleep mode OR was fully stopped/powered off.
The second one counts the number of times the heads were parked in the landing area. You can get the heads to go to the landing area and keep the platters spinning, but you cannot
spin down without parking the heads. So, wherever you spin down the drive both of those smart parameters are incremented. When the drive is just parked, only Load/Unload Cycle Count is incremented.
While a lot of parking is not bad, a lot of start/stops are bad.
The <<hdparm -S >> in the power management scripts that I'm pointing my finger at controlls the spinup/spindown and not just the parking of the heads. And the default timeout for that is not only uninspired, but potentially dangerous. This is what actually has the greatest potential to kill the drive prematurely. So, in your smartctl output look for a high start/stop count , not for a high load/unload count .
These are the values for my laptop that still runs Dapper :
4 Start_Stop_Count 0x0012 100 100 000 Old_age Always - 749
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 386
193 Load_Cycle_Count 0x0012 036 036 000 Old_age Always - 646281
The hard drive is only about 1 year old. I'm not worried about Load_Cycle_Count (which is way over 600k ). I would worry about a high Start_Stop_Count .