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[tidy]

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[razel]

3.5" drives in a desktop that isn't moving may very well not need head parking during idle. However the majority of computers sold are laptops. As for additional wear, I think it's just armchair opinions from those who don't design HDDs.

I'd rather believe that those designing these drives know better than us about it. I was 1st introduced to head parking in the early 90's. The only difference back then was it parked the head during power down. I assume now it parks heads when you tell it in the 'power options'.

 

[zir_blazer]

As far that I know, there is extra wear. As a mechanical device, if the head gets parked then unparked often, the wear is superior that if it was just in constant motion. Its very similar to thermal cycles in semiconductors.

 

[tidy]

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[Kougar]

Of course it causes wear, that's why HDDs have a load cycle counter and MTBF rating for said head parking.

That said head parking wear is generally not an issue unless you use a drive with aggressive head parking (meaning it was designed as a low power storage drive) and do something silly like make it an OS drive. That would generate excessive head parking wear.

To quote an Anandtech article:

Power Management Features: Some hard drives adopt aggressive head parking and disk spindown to save on power. For example, the WD Green drives were guilty of parking the head after just 8 seconds of inactivity. This increases the load cycle count unnecessarily (drives are usually rated for 300K cycles).

In my opinion head parking causes less wear on a drive as compared to spinning up the platters. Just like a car engine, the starting/ignition and the acceleration are the times of the most wear on a car engine, yet maintaining a steady highway speed causes very little wear by comparison. Hard drive platters are no different and so far I've had very good results with drive longevity on those I disable the system spin-down timer on.

 

[tidy]

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[Concillian]

Here's the history:

Heads used to land on the platters. In the very early days, this was no problem. Platters were rough. Sometime in the 80s or so, platter roughness started coming down to the point where the heads would sometimes STICK to the platter just from how smooth and close the head and platter was. The motors that seek the heads would need to be beefy just to unstick the heads from the platter. Back then, sometimes you'd come across drives that wouldn't work that would start working again if you gave them a good *thwack* on the side while it was trying to spin up, as this would free the heads.

At that point, they started to make a portion of the platter rougher (the so called "landing zone",) and land there. First with something akin to wet sanding the smoothly polished substrate, later they developed machines that would precision burn this landing zone with a pattern of tiny bumps a couple hundred angstroms tall with lasers. Both of those methods would have wear issues. The protective coatings over the peaks and on the heads would eventually wear out. This failure mode was strongly correlated with contact start / stops.

Modern drives have none of that. Modern drives fully unload the heads from the media. There are still things that can go wrong, but there is MUCH, MUCH less wear concern. The wear happens on a part of the assembly specifically designed to handle that function rather than on the actual heads and platters. Additional wear protection there doesn't degrade the areal density potential like it does if you add thickness to a coating between the heads and the platter, so it can be relatively much beefier.

So yes, there is a scientific basis for the concern. The fear is founded in fact. However, in practice, it is largely outdated to be overly concerned about.

 

[tidy]

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[Zxian]

I really don't know what to think about this. If the head parking wear wasn't a problem, then why bother specifying a 'Load/Unload Cycles' rating on the drive's data sheet. And if they're going to give such a rating, then why do they configure the drive to constantly park with reckless disregard for that rating.

Unless you have a statistic that directly tells you a drive is failing (e.g. bad sector count), don't rely on SMART data to gauge the status of a drive. The Load/Unload Cycles reading varies from one drive to the next (e.g. what it represents) and also has no correlation with the manufacturer reliability specs.

It's a non issue. I've got a WD Green drive here with a LLC count of 2.4 million. No ticks, no funny noises, no odd performance.

It's not a definitive metric, so people should stop worrying about it.

 

[Red Squirrel]

It's probably not so much the head parking but the platter spin down/up as it's probably harder on the motor. Though the head parking too probably has some wear. anything that moves has some wear, and constant head parking means it moves more.

The biggest issue with head parking/spin down is in raid though, because that will get detected as a failed drive. My fear with this trend of "green" drives is that all consumer drives will eventually have this "feature" which will force home server users to buy enterprise drives.

 

[sxr7171]

Is this where the alleged wear is happening?

I have my ST2000DM001 connected with nothing on it, it's not even formatted, yet it's still parking on a regular basis. I hear it all the time, and in ~48 hours the LCC has risen from 279 to 368, despite only 5 system startup/shutdown cycles in that time.

I really don't know what to think about this. If the head parking wear wasn't a problem, then why bother specifying a 'Load/Unload Cycles' rating on the drive's data sheet. And if they're going to give such a rating, then why do they configure the drive to constantly park with reckless disregard for that rating.

Is that factor the limiting factor in the MTBF? I'm sure statistically it adds a small amount to the risk of drive failure but they may have improvements in other modes of failure statistically speaking.

I'm inclined to think it's a myth. Other issues like a noisier drive are still real issues.

 

[sxr7171]

It's probably not so much the head parking but the platter spin down/up as it's probably harder on the motor. Though the head parking too probably has some wear. anything that moves has some wear, and constant head parking means it moves more.

The biggest issue with head parking/spin down is in raid though, because that will get detected as a failed drive. My fear with this trend of "green" drives is that all consumer drives will eventually have this "feature" which will force home server users to buy enterprise drives.

I think that's the ploy basically. For example WD charges more for the "NAS" version of the green drive that just has this "feature" turned off.

 

[UaVaj]

this is one of those stupid features ever to be implemented on a performance desktop.

on a portable which is running on battery. make sense to parking the head to save a little power at the expense of head wear.
on a performance desktop. just simply stupid. no other way around.

never had a hard drive die while running. ever.
had a 1/2 dozen plus died from being power down and unable to function after power up.
most recent one was a seagate 3tb that died from going to sleep.
go figure.

every time that head parks - you playing russian roulette with your data.
as for spindle motor. never had one quit either. ever.

still not buying this. ask western digital. ask the difference between green and red drives.

 

[Zxian]

every time that head parks - you playing russian roulette with your data.

Re-read my earlier reply. The SMART data that people read has zero correlation to the manufacturer reliability info.

 

[code65536]

It begs the question, though, why HDD manufacturers all cite figures for load/unload cycles if they're not that important? Esp. in WD's case, why make a drive that cycles load and unload so frequently that you're all but guaranteed to surpass the 300K rating? Either their spec sheet is wrong, or the drive's design is off. Pick one.

 

[Zxian]

It begs the question, though, why HDD manufacturers all cite figures for load/unload cycles if they're not that important? Esp. in WD's case, why make a drive that cycles load and unload so frequently that you're all but guaranteed to surpass the 300K rating? Either their spec sheet is wrong, or the drive's design is off. Pick one.

Or the SMART data you're reading doesn't relate to what you think it does. Why are people bothering to measure a statistic that has no proven correlation with drive failures? Individual user's anecdotal evidence is useless, and yet people are still willing to follow it. Furthermore, you're given a specific warranty period. Whether or not the drive has exceeded some SMART metric has no bearing on whether or not you'll get support.

Work at Google on over 100,000 drives over a 9-month period found correlations between certain SMART information and actual failure rates. In the 60 days following the first off-line scan uncorrectable error on a drive (SMART attribute 0xC6 or 198), the drive was, on average, 39 times more likely to fail than it would have been if no such error occurred. First errors in reallocations, offline reallocations (SMART attributes 0xC4 and 0x05 or 196 and 5) and probational counts (SMART attribute 0xC5 or 197) were also strongly correlated to higher probabilities of failure. Conversely, little correlation was found for increased temperature and no correlation for usage level. However, the research showed that a large proportion (56%) of the failed drives failed without recording any count in the 'four strong S.M.A.R.T. warnings' identified as scan errors, reallocation count, offline reallocation and probational count. Further, 36% of drives failed without recording any S.M.A.R.T. error at all (except temperature), meaning that S.M.A.R.T. data alone was of limited usefulness in anticipating failures.

Link



I choose to buy WD drives because they have good support, a reasonable warranty period, and good prices. The data that BackBlaze released supports my decision further. The fact that I've had good luck so far (note: luck) when it comes to reliability with the 30+ drives I've purchased for myself, friends, and family has nothing to do with it. I don't bother monitoring SMART data on a regular basis because it usually doesn't matter.

 

[UaVaj]

The data that BackBlaze released supports my decision further.

BackBlaze. Reallie?

WD Green and Seagate LP are bottom of the barrel. :whiste:

ever wonder what the major differences between WD Green and Seagate LP from the rest of the other drives?

 

[tidy]

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[Zxian]

BackBlaze. Reallie?

WD Green and Seagate LP are bottom of the barrel. :whiste:

ever wonder what the major differences between WD Green and Seagate LP from the rest of the other drives?

The WD Greens are rated better than any Seagate they provided detailed specs for. Your notion that low-power drives are inherently less reliable doesn't hold water given the data in the link you provided.

The only negative mention that WD Greens were given was that BackBlaze won't use the 3TB models due to errors caused by the vibrations in their storage pods. When was the last time you shoved 45 drives into your computer? This should be a non-issue for most consumers.

Are you sure about that? I know that the way other SMART stats are reported can vary between manufacturer (like 'raw read error rate'), but I'm sure LCC is just that. If you watch it, every 'tick' of the LCC will coincide with and audible head park.

That again depends on the drive. The drive mentioned above was once a part of an eight drive RAID5 array. Given the rate of LLC/hour, it means that while the system was active I would have heard about eight head parks every minute. This simply wasn't the case. You can see my original build post here. The system was quiet enough to hear the drives initially spin up (especially with staggered spinup), but once they were going it was nearly inaudible.


I haven't seen any definitive proof that high LLC causes drive failures (which is what you're really asking about). The only thing you'll find is anecdotal evidence of some people who correlate LLC and head parking with reliability. Hard drives are always a lottery. I'd rather go with a company with reliable support over just about everything else. You do have good backups, right?

 

[UaVaj]

 

[Zxian]

Do you have anything constructive to add? Or you just going to keep rolling your eyes without backing anything up?

Find me something definitive to back up your claims. Even the source you provided didn't support your opinion.

 

[bluetartle7]

12

 

[bononos]

Yes its puzzling why WD/Seagate/Hitachi continues to list 300,000 llc in their specs. Hitachi 3Tb is 600k.

There was one model of WD greens EARS or earlier(I forgot) which gave more problems than usual which made people suspect that it could be due to excessive head parking. Then the later models lengthened the head parking timeout to 30s. I don't think Seagate or Hitachi have such an aggressive head parking setting but the figures don't show newer WD greens having excessive return rates or failures.

 

[razel]

@zxian... I gave up and moved on. It's totally fine to help educate others who know less. But the Internet lately is full of those who just want to fight mainly because their feelings get hurt that whatever they read off the Internet is wrong. If I were them, I'd seriously get a job as a lawyer.

 

[Concillian]

It begs the question, though, why HDD manufacturers all cite figures for load/unload cycles if they're not that important? Esp. in WD's case, why make a drive that cycles load and unload so frequently that you're all but guaranteed to surpass the 300K rating? Either their spec sheet is wrong, or the drive's design is off. Pick one.

Because customers of drive manufacturers don't update their specifications for obsolete ones.

They had a problem 10 years ago with this issue, that spec stays on their spec sheet FOREVER. Regardless as to whether the design has changed to obsolete that as a spec.

People were once sensitive to the issue, and people have long memories on this kind of thing. So it remains a spec.