I set up a home server about a year ago, using Ubuntu server (10.04 LTS at the moment), four disks in RAID 5 for storage (WD Green 1.5 TB) and a laptop drive for the OS.

Today the output of smartctl, a command line utility for checking the SMART attributes of a hard drive, tells me that the primary OS drive has had no less than 186,000 start-stop cycles in 325 days and may be nearing the end of its lifespan.

The smartctl output is in "normalized values", in this case a number between 200 and 000, where 200 is "brand new" and 000 means "worn out". My disk gets 001.

So I wonder what happened: 186k start/stop cycles in 7820 hours is about one start/stop per 2.5 minutes around the clock. This seems somewhat excessive for a computer that sees actual use once or twice per day. (The RAID disks are normal, averaging to one start/stop per day, as expected.)

Does anyone have similar experiences, or pointers to what might be the issue here?

Specifically I'd like to know

• Why the massive start/stop count? Do I have some sort of configuration issue? Could there be a background service that is causing trouble?
• Could having a laptop disk as the OS drive be part of the problem? Can anyone confirm or deny this?

Here is the /etc/hdparm.conf configuration

/dev/sda {
  apm = 127
  spindown_time = 120
}

and the most relevant parts of smartctl --attributes /dev/sda:

smartctl version 5.38 [x86_64-unknown-linux-gnu] Copyright (C) 2002-8 Bruce Allen

=== START OF READ SMART DATA SECTION ===
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
  4 Start_Stop_Count        0x0032   001   001   000    Old_age   Always       -       185875
  9 Power_On_Hours          0x0032   090   090   000    Old_age   Always       -       7820
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       109
193 Load_Cycle_Count        0x0032   118   118   000    Old_age   Always       -       246833
194 Temperature_Celsius     0x0022   107   098   000    Old_age   Always       -       36

As I generally prefer my drives to last more than a year, any advice is appreciated.