[mythtvnz] HDD Load Cycle Count ticking over too fast

[David Moore]

Aargh! After my recent disk problem I decided to delve into smartmon 
again. First thing I noticed was one drive had much higher 193 
Load_Cycle_Count value than the other, older drive. So started watching 
it and it ticks up every 30s or so IF the system is idle. Just watched 
and recorded from the same disk and during this time the count didn't 
increase which makes sense since it was busy writing/reading 100% of the 
time.

The old drive, which has the OS on it, has sat at the same load cycle 
count during this time.

This is the problem drive:
Device Model:     WDC WD20EARS-00MVWB0

ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE 
UPDATED  WHEN_FAILED RAW_VALUE
   4 Start_Stop_Count        0x0032   100   100   000    Old_age 
Always       -       725
   9 Power_On_Hours          0x0032   095   095   000    Old_age 
Always       -       4206
  12 Power_Cycle_Count       0x0032   100   100   000    Old_age 
Always       -       723
193 Load_Cycle_Count        0x0032   193   193   000    Old_age   Always 
       -       23963
194 Temperature_Celsius     0x0022   117   109   000    Old_age   Always 
       -       33


Older drive:
Device Model:     WDC WD10EADS-00L5B1

Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE 
UPDATED  WHEN_FAILED RAW_VALUE
   4 Start_Stop_Count        0x0032   098   098   000    Old_age 
Always       -       2961
   9 Power_On_Hours          0x0032   085   085   000    Old_age 
Always       -       11487
  12 Power_Cycle_Count       0x0032   099   099   000    Old_age 
Always       -       1219
193 Load_Cycle_Count        0x0032   200   200   000    Old_age   Always 
       -       2961
194 Temperature_Celsius     0x0022   116   109   000    Old_age   Always 
       -       34

You can see how the load cycle count relative to other counts is much 
different between the two. Both are WD Green drives. The older one has 
the OS on an EXT4 partition plus an NTFS partition while the newer one 
has a single JFS partition.

Any ideas about whether it's the file system (JFS vs EXT4) or OS setting 
or BIOS or HDD firmware that's causing the problem? I can't grasp why 
the disk should spin down, park, then spin up again when it's idle. I'm 
99% sure there should be no activity on the drive unless myth is 
recording or playing.

BTW the load cycle count went from 23963 to 23971 while writing this.