# HDD load_cycle_count lifespan & hdparm -B weirdness

## dasPaul

Hi there 

I just hope someone had the same thoughts in the past

and can enlighten me a little bit. 

I got a new cheap 2TB 2.5 harddisk (M9T). I read those drives have an extreme load_cycle_count because they are labeled as MOBILE Drive.

To prevent errors due to shock of movement the manufacturer has set the drive to park its head as often as needed at the cost of lifetime.

The specs sheet of the M9T drive labels "<600000 Controlled Ramp Load/Unload". My guess is this value correspons with the Load_Cycle_count that can be read with the command "smartctl -A /dev/sdX". I know those values are not that meaningful and the disk does not instant die after it reaches the value because I also have an 3 years old 500GB Samsung Drive that still runs without errors and already has 8 MILLION cycles.

Since I dont move my drive through the wilderness, I use it in a home server, would it harm the drive if I lower the cycles by unsing the hdparm command? 

As I first run the new drive I observed a cycle count of ~28 cycles per hour which estimates a livespan of 600000/(28*24*365)=2.4years. In my mind thats to short. I own another samsung drive that has only 5 cycles per hour.

First thing I did was to get the actual apm value for the drive with "hdparm -B /dev/sdX". It was "Disabled" respectively set to 255.

So with APM disabled in the drive LCC grows steady at 28 c/h.

I could stop that by setting "hdparm -B 254 /dev/sdX". With that I was not able to notice any growth of LLC in the past 20 hours hopefully increasing the drives lifespan.

Now I stuck at hdparm -B [1-128;128-254]. Set between 1-128 it is said the drive will spindown after a given time (which every manuf. seems to do different), set between 128-245 the drive does.. something? but what? Does it any power management or enter a special state?

----------

## eccerr0r

I haven't seen a drive die yet to load cycles but keep in mind that they never intended laptop/mobile drives to be connected 24/7 and likely will invalidate your warranty when they see your power on hours so high...

To stop load count from increasing, you have to disable it, and also disable spinup/spindown (as this also causes a load count)  Unfortunately the power save modes are manufacturer specific.

It's a "damned if you do, damned if you don't" situation and really should be getting server quality disks that were intended to be constantly powered up.  Or an SSD.

This is my 2GB PCMCIA HDD that has been in the FAILING_NOW state for several YEARS:

```
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE

  9 Power_On_Hours          0x0032   008   008   050    Old_age   Always   FAILING_NOW 36909

225 Load_Cycle_Count        0x0032   023   023   070    Old_age   Always   FAILING_NOW 773192

```

I'm only torturing this device because these things are fairly worthless nowadays...

----------

## dasPaul

 *eccerr0r wrote:*   

> 24/7 and likely will invalidate your warranty when they see your power on hours so high...

 

Are you aware of such a case? I just cant imagine that they wont apply warranty due of high power_on_hours and I also cant find any point of excessive "powered on" in the warranty regulation.

----------

## eccerr0r

I have heard anecdotal reports people have been denied warranty reports due to POH, but luckily I have not had too many drives fail like that.  It's the bathtub curve, mostly.

----------

## dasPaul

Ok, thank you for you thoughts. I think SSD is still no option for me because I do intensive file movements on the disk (>30GB/day, astronomy image processing...). 

I played around with hdparm's apm settings. I think I've found a middleway. 

for the Samsung M9T:

hdparm -B 255 disables APM, but the drive seems to do some internal "whatever" and drives the cylces up 28 per hour

hdparm -B 1-127 spindown after 30s

hdparm -B 128-254 no spindown but also high cycles increment

this is my setting now:

hdparm -B 254 & hdparm -S 120 spindown after 10m without any further increament of power_on_hours and cycles except the spindown/up ones.

----------

## szatox

 *Quote:*   

>  I do intensive file movements on the disk (>30GB/day, astronomy image processing...). 

  you're not going to kill it any time soon moving only 30GB daily. In fact moving 300GB daily won't hurt much either. I'd rather consider SSD for stuff like that than for a regular desktop where you can cache everything you need in RAM at half of SSD's price.

----------

## dasPaul

Its not only astronomy stuff but sometimes I move a whole gentoo installation from disk to disk. An SSD is to expensive and to small for my need. I had an Sony Ultrabook with an Intel 250GB SSD and I did three gentoo installations and two windows on it. After that the disk started to fail. Maybe I was doing something wrong.

----------

