Summary: Re: Spin down HDD after disk sync or before power off

[Paul Wootton]

  On 10/21/10 15:20, Dag-Erling Smørgrav wrote:
> Bruce Cran<bruce at cran.org.uk>  writes:
>> The Ubuntu issue was what I was thinking of - I got that mixed up with
>> the aggressive power management of the WD EARS drives.
> The entire Green series, actually, which includes models such as the
> EADS, AARS etc., but there's more to them than that - the central
> feature is their dynamically adjusted rotational speed, which allows
> them to conserve power without spinning all the way down.
>
> DES

Actually, the green series does spin all the way down, well at least the 
drive I have does.
Here is the output from one of my drives, that I do not think has long 
left to live.

=== START OF INFORMATION SECTION ===
Model Family:     Western Digital Caviar Green family
Device Model:     WDC WD5000AADS-00M2B0
Serial Number:    WD-WMAV51882791
Firmware Version: 01.00A01
User Capacity:    500,107,862,016 bytes
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   8
ATA Standard is:  Exact ATA specification draft version not indicated
Local Time is:    Thu Oct 21 23:31:35 2010 BST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
....
SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      
UPDATED  WHEN_FAILED RAW_VALUE
   1 Raw_Read_Error_Rate     0x002f   200   200   051    Pre-fail  
Always       -       0
   3 Spin_Up_Time            0x0027   111   104   021    Pre-fail  
Always       -       7425
   4 Start_Stop_Count        0x0032   100   100   000    Old_age   
Always       -       98
   5 Reallocated_Sector_Ct   0x0033   200   200   140    Pre-fail  
Always       -       0
   7 Seek_Error_Rate         0x002e   100   253   000    Old_age   
Always       -       0
   9 Power_On_Hours          0x0032   093   093   000    Old_age   
Always       -       5295
  10 Spin_Retry_Count        0x0032   100   253   000    Old_age   
Always       -       0
  11 Calibration_Retry_Count 0x0032   100   253   000    Old_age   
Always       -       0
  12 Power_Cycle_Count       0x0032   100   100   000    Old_age   
Always       -       96
192 Power-Off_Retract_Count 0x0032   200   200   000    Old_age   
Always       -       95
193 Load_Cycle_Count        0x0032   001   001   000    Old_age   
Always       -       781014
194 Temperature_Celsius     0x0022   120   102   000    Old_age   
Always       -       27
196 Reallocated_Event_Count 0x0032   200   200   000    Old_age   
Always       -       0
197 Current_Pending_Sector  0x0032   200   200   000    Old_age   
Always       -       0
198 Offline_Uncorrectable   0x0030   200   200   000    Old_age   
Offline      -       0
199 UDMA_CRC_Error_Count    0x0032   200   200   000    Old_age   
Always       -       0
200 Multi_Zone_Error_Rate   0x0008   200   200   000    Old_age   
Offline      -       0


The datasheet for these drive 
<http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-701229.pdf>http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-701229.pdf 
says
"Reliability/Data Integrity
Load/unload cycles (3)         300,000
Limited Warranty (years) (4)
(3) Controlled unload at ambient condition
(4) The term of the limited warranty my vary by region"

Also 
http://wdc.custhelp.com/cgi-bin/wdc.cfg/php/enduser/std_adp.php?p_faqid=5357
"(drive has been validated to 1 million load/unload cycles without issue)"

Im already at 781014 load cycles, yet the drive is only about 7 months 
old. Doing the math, I am getting a load/unload cycle about every 24.5 
seconds
Another 2 months and I will be knocking on for 1 million load/unload 
cycles....

As DES has already said, for most people the extra load/unload cycles 
when rebooting a computer will not be an issue at all and is far more 
desirable than an emergency park when powering down


Paul