Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

I have seen various comments like "we leave our servers running 24/7
because powering up a hard drive causes more wear than leaving it
running." I think it's mostly laziness and apathy about conserving
energy. The TiVo forums discuss it a lot because a standard TiVo HD
runs all the time, buffering 30 minutes of whatever channel it's left
on.

Do IT people who leave servers running 24/7 ever have much choice of
NOT leaving them on 24/7? If not, how can they make scientific
comparisons of drive-bearing life? As long as the head isn't moving,
bearing life seems to be the main concern. On a home PC left on all day
it's far less likely that the drive will be doing anything but spinning
at high RPM for no real reason.

I've heard similar claims that the "shock" of turning on a light bulb
is worse than leaving it on all the time. Usually those comments came
as a way to excuse energy consumption after a debate on the merits of
waste. In reality, bulbs have a finite hours rating and will burn out
faster the longer they are left on, as long as they aren't flipped on
and off as torture. CFL bulbs (w/ballast) don't like to be switched on
and off quickly, but I can't imagine them burning out faster if you
only cycle on/off once in 10 minutes or so.

Would anyone claim that car wheel bearings get as much wear when you
pull out of the driveway vs. a 500 mile nonstop trip? In that case, the
"spin up" would be when you first move the car after sitting. What
exactly causes the "big shock" when a hard drive spins up? The heat
generated from constant spinning would seem to far outweigh it. Why
does Windows have a "Turn off hard disks" feature in Power options if
not to reduce bearing wear?

If anyone has thorough technical articles on hard drive wear, please
post. Specifically, what is so torturous about spinning up the drive,
and how can that brief cycle be quantified, damage-wise against
constant spinning with higher heat levels?

Thanks.

JT

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

More than continuing to spin, yes.

There's a reason for the number of start stop
cycles specified in the hard drive datasheets.

Jack Tyler <jctyler_67@yahoo.com> wrote in message
news:1115954512.453949.223990@g49g2000cwa.googlegroups.com...

> I have seen various comments like "we leave our
> servers running 24/7 because powering up a hard
> drive causes more wear than leaving it running."

That is correct.

> I think it's mostly laziness

Nope.

> and apathy about conserving energy.

Yep, what a hard drive uses is a fart in the bath, 5W or so.

> The TiVo forums discuss it a lot because a standard TiVo HD runs
> all the time, buffering 30 minutes of whatever channel it's left on.

> Do IT people who leave servers running 24/7 ever
> have much choice of NOT leaving them on 24/7?

Yes, the drives can be configured to spin down on inactivity.

> If not, how can they make scientific
> comparisons of drive-bearing life?

There's a reason for the limit to start stop cycles
in the hard drive manufacturer's data sheets.

> As long as the head isn't moving, bearing
> life seems to be the main concern.

You dont get many hard drives bearings failing anymore.

> On a home PC left on all day it's far less likely that the drive will
> be doing anything but spinning at high RPM for no real reason.

Sure.

> I've heard similar claims that the "shock" of turning
> on a light bulb is worse than leaving it on all the time.

That can be overstated, but there certainly is a considerable turnon
shock with incandescent bulbs. Not relevant to hard drives tho.

> Usually those comments came as a way to excuse energy
> consumption after a debate on the merits of waste.

Sure.

> In reality, bulbs have a finite hours rating and
> will burn out faster the longer they are left on,
> as long as they aren't flipped on and off as torture.

Sure, but irrelevant to hard drives.

> CFL bulbs (w/ballast) don't like to be switched on and
> off quickly, but I can't imagine them burning out faster
> if you> only cycle on/off once in 10 minutes or so.

Yes, the turnon effect is completely different to incandescent bulbs.

> Would anyone claim that car wheel bearings get as much wear
> when you pull out of the driveway vs. a 500 mile nonstop trip?

Completely different to hard drives.

> In that case, the "spin up" would be
> when you first move the car after sitting.

And that is completely different to a hard drive.

> What exactly causes the "big shock" when a hard drive spins up?

Basically the spinup torque.

> The heat generated from constant
> spinning would seem to far outweigh it.

Anyone with a clue ensures that the drive doesnt get hot.

> Why does Windows have a "Turn off hard disks"
> feature in Power options if not to reduce bearing wear?

To reduce power used, just like with monitors and motherboards.

> If anyone has thorough technical articles
> on hard drive wear, please post.

The start stop cycles specified in the hard drive datasheets
are the most imporant numbers. They can be exceeded by
a startup every hour surprisingly quickly.

> Specifically, what is so torturous about spinning up the drive,
> and how can that brief cycle be quantified, damage-wise
> against constant spinning with higher heat levels?

Thermal cycling also isnt good for most electronic devices.

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

"Jack Tyler" <jctyler_67@yahoo.com> wrote in news:1115954512.453949.223990
@g49g2000cwa.googlegroups.com:

> I have seen various comments like "we leave our servers running 24/7
> because powering up a hard drive causes more wear than leaving it
> running." I think it's mostly laziness and apathy about conserving
> energy. The TiVo forums discuss it a lot because a standard TiVo HD
> runs all the time, buffering 30 minutes of whatever channel it's left
> on.
>
> Do IT people who leave servers running 24/7 ever have much choice of
> NOT leaving them on 24/7? If not, how can they make scientific
> comparisons of drive-bearing life? As long as the head isn't moving,
> bearing life seems to be the main concern. On a home PC left on all day
> it's far less likely that the drive will be doing anything but spinning
> at high RPM for no real reason.
>
> I've heard similar claims that the "shock" of turning on a light bulb
> is worse than leaving it on all the time. Usually those comments came
> as a way to excuse energy consumption after a debate on the merits of
> waste. In reality, bulbs have a finite hours rating and will burn out
> faster the longer they are left on, as long as they aren't flipped on
> and off as torture. CFL bulbs (w/ballast) don't like to be switched on
> and off quickly, but I can't imagine them burning out faster if you
> only cycle on/off once in 10 minutes or so.
>
> Would anyone claim that car wheel bearings get as much wear when you
> pull out of the driveway vs. a 500 mile nonstop trip? In that case, the
> "spin up" would be when you first move the car after sitting. What
> exactly causes the "big shock" when a hard drive spins up? The heat
> generated from constant spinning would seem to far outweigh it. Why
> does Windows have a "Turn off hard disks" feature in Power options if
> not to reduce bearing wear?
>
> If anyone has thorough technical articles on hard drive wear, please
> post. Specifically, what is so torturous about spinning up the drive,
> and how can that brief cycle be quantified, damage-wise against
> constant spinning with higher heat levels?

You posted from google groups...so what did the archive say about the past
discussions on this topic?

--
Minister of All Things Digital & Electronic, and Holder of Past Knowledge
stile99@email.com. Cabal# 24601-fnord | Sleep is irrelevant.
I speak for no one but myself, and |Caffeine will be assimilated.
no one else speaks for me. O- | Decaf is futile.

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

my observations of the newer ata drives in the last year was they succumb
easily to heat than constant booting. I had a server that run 24/7 for weeks
and some of the drives needed to be replaced every few months. Much faster
than other computers that shutdown in the same environment. It could also be
because of the cheap maxtor plus 8 the raid was using, hard to tell but keep
those drives cool I say.


"Jack Tyler" <jctyler_67@yahoo.com> wrote in message
news:1115954512.453949.223990@g49g2000cwa.googlegroups.com...
>I have seen various comments like "we leave our servers running 24/7
> because powering up a hard drive causes more wear than leaving it
> running." I think it's mostly laziness and apathy about conserving
> energy. The TiVo forums discuss it a lot because a standard TiVo HD
> runs all the time, buffering 30 minutes of whatever channel it's left
> on.
>
> Do IT people who leave servers running 24/7 ever have much choice of
> NOT leaving them on 24/7? If not, how can they make scientific
> comparisons of drive-bearing life? As long as the head isn't moving,
> bearing life seems to be the main concern. On a home PC left on all day
> it's far less likely that the drive will be doing anything but spinning
> at high RPM for no real reason.
>
> I've heard similar claims that the "shock" of turning on a light bulb
> is worse than leaving it on all the time. Usually those comments came
> as a way to excuse energy consumption after a debate on the merits of
> waste. In reality, bulbs have a finite hours rating and will burn out
> faster the longer they are left on, as long as they aren't flipped on
> and off as torture. CFL bulbs (w/ballast) don't like to be switched on
> and off quickly, but I can't imagine them burning out faster if you
> only cycle on/off once in 10 minutes or so.
>
> Would anyone claim that car wheel bearings get as much wear when you
> pull out of the driveway vs. a 500 mile nonstop trip? In that case, the
> "spin up" would be when you first move the car after sitting. What
> exactly causes the "big shock" when a hard drive spins up? The heat
> generated from constant spinning would seem to far outweigh it. Why
> does Windows have a "Turn off hard disks" feature in Power options if
> not to reduce bearing wear?
>
> If anyone has thorough technical articles on hard drive wear, please
> post. Specifically, what is so torturous about spinning up the drive,
> and how can that brief cycle be quantified, damage-wise against
> constant spinning with higher heat levels?
>
> Thanks.
>
> JT
>

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

> Many drives are now using
> hydrostatic bearings, which will eliminate *some* of the low pressure
> problem at startup depending on how the pressure is supplied.

BTW, just to be clear, hydrostatic bearings are used in HDD's to reduce
noise, not to extend bearing life.

Randy S.

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

Fri, 13 May 2005 08:17:45 -0400, rswittNO@SPAMgmail.com suggested:
:
: Why is it up to the IT people to do the scientific comparisons, isn't
: that up to the manufacturer? As an IT person who *also* used to design
: bearings (ball, journal *and* roller) there *are* both wear and startup
: issues. Most catastrophic failures occur at startup unless there is an
: unrelated cause of failure (like an overheat condition, overloading or
: oil starvation).

One trick that the systems guy where I work has told me about is that
before he deploys a server, he frequently powers it on and off over the
course of a week or two to try to get any marginal hard disks to fail (and
then replace them) before it goes into live use.

--
agreenbu @ nyx . net andrew michael greenburg

Archived from groups: alt.video.ptv.tivo (More info?)

On 13 May 2005 23:51:18 GMT, andrewunix <agreenbu@nyx.net> wrote:

>One trick that the systems guy where I work has told me about is that
>before he deploys a server, he frequently powers it on and off over the
>course of a week or two to try to get any marginal hard disks to fail (and
>then replace them) before it goes into live use.

Running a good burn in program will do that as well, for the same reason.

--
Michael Cecil
http://home.comcast.net/~macecil/
http://home.comcast.net/~safehex/

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

Jack Tyler wrote:

> I have seen various comments like "we leave our servers running 24/7
> because powering up a hard drive causes more wear than leaving it
> running."

This is the conventional wisdom. And it's not just disks. Thermal cycling
used to be a serious problem with computers--that's why memory sockets have
latches now. On an original IBM PC that had been running for a couple of
years, sometimes the memory chips would walk completely out of the socket
due to repeated thermal cycling.

> I think it's mostly laziness and apathy about conserving
> energy.

Shutting down a large server farm is not something to be done lightly.
Bringing it down and back up in an orderly fashion might take more than one
night.

> The TiVo forums discuss it a lot because a standard TiVo HD
> runs all the time, buffering 30 minutes of whatever channel it's left
> on.

Yep, and they seem to last and last.

> Do IT people who leave servers running 24/7 ever have much choice of
> NOT leaving them on 24/7?

Depends on the circumstances.

> If not, how can they make scientific
> comparisons of drive-bearing life?

The viewpoint is generally based on experience with other mechanical
devices.

> As long as the head isn't moving,
> bearing life seems to be the main concern.

Even if the head is moving, bearing life is the main concern as far as
_wear_ goes. The heads run on an air bearing--the wear is negligible.

However disk seldom die of bearing failure--generally the failure is a crash
or an electronics failure.

> On a home PC left on all day
> it's far less likely that the drive will be doing anything but spinning
> at high RPM for no real reason.

Maybe on _your_ system.

> I've heard similar claims that the "shock" of turning on a light bulb
> is worse than leaving it on all the time. Usually those comments came
> as a way to excuse energy consumption after a debate on the merits of
> waste. In reality, bulbs have a finite hours rating and will burn out
> faster the longer they are left on, as long as they aren't flipped on
> and off as torture. CFL bulbs (w/ballast) don't like to be switched on
> and off quickly, but I can't imagine them burning out faster if you
> only cycle on/off once in 10 minutes or so.

You ever notice how light bulbs generally blow when you turn them on, not
when they are just sitting there giving off light? It's called "thermal
shock" and it's a real phenomenon.

> Would anyone claim that car wheel bearings get as much wear when you
> pull out of the driveway vs. a 500 mile nonstop trip? In that case, the
> "spin up" would be when you first move the car after sitting. What
> exactly causes the "big shock" when a hard drive spins up? The heat
> generated from constant spinning would seem to far outweigh it. Why
> does Windows have a "Turn off hard disks" feature in Power options if
> not to reduce bearing wear?
>
> If anyone has thorough technical articles on hard drive wear, please
> post. Specifically, what is so torturous about spinning up the drive,
> and how can that brief cycle be quantified, damage-wise against
> constant spinning with higher heat levels?

The basic problem with any bearing is that at rest the mass supported by the
bearing causes the rotating assembly to sink though the lubricant until it
is touching something solid. When the device of whatever kind is started,
there is a period before the lubricating film reestablishes itself in which
there is metal-to-metal contact. Thus most of the wear occurs at startup.
This is exacerbated by the fact that the lubricant is cold and thus does
not flow well.

The "heat generated from constant spinning", assuming that the drive is not
being operated outside its rated temperature range, has negligible effect
on the durability of the mechanical components--it would have more effect
on the electronics but the electronic components are outside the capsule.

> Thanks.
>
> JT

--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

Randy S. wrote:

>> Many drives are now using
>> hydrostatic bearings, which will eliminate *some* of the low pressure
>> problem at startup depending on how the pressure is supplied.
>
> BTW, just to be clear, hydrostatic bearings are used in HDD's to reduce
> noise, not to extend bearing life.

Actually, fluid dynamic bearings (they are not "hydrostatic" ) have sliding
contact at startup, where a ball or roller will normally have rolling
contact unless the lubricant is very stiff. So the FDB will have more wear
at startup.

> Randy S.

--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

Jack Tyler wrote:

> Would anyone claim that car wheel bearings get as much wear when you
> pull out of the driveway vs. a 500 mile nonstop trip?

Would anyone claim that crankshaft bearings get as much wear when you
start up a cold engine vs. driving for a couple of hours? Yes.

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

Joe Smith wrote:

> Jack Tyler wrote:
>
> > Would anyone claim that car wheel bearings get as much wear when
you
> > pull out of the driveway vs. a 500 mile nonstop trip?
>
> Would anyone claim that crankshaft bearings get as much wear when you
> start up a cold engine vs. driving for a couple of hours? Yes.

I understand lubrication phenomena but I'm trying to find a way to
quantify startup wear vs. constant running wear. Maybe it's just hard
to quantify without a lot of guesswork.

JT

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

Howard wrote:

> > If anyone has thorough technical articles on hard drive wear,
please
> > post. Specifically, what is so torturous about spinning up the
drive,
> > and how can that brief cycle be quantified, damage-wise against
> > constant spinning with higher heat levels?
>
> You posted from google groups...so what did the archive say about the
past
> discussions on this topic?

Lots of hearsay in past discussions. This thread has been a lot more
informative.

JT

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

Rod Speed wrote:

> There's a reason for the number of start stop
> cycles specified in the hard drive datasheets.

I think I need to find and read those datasheets. If you have any quick
links, please post.

JT

Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.video.ptv.tivo (More info?)

Rod Speed wrote:

> The start stop cycles specified in the hard drive datasheets
> are the most imporant numbers. They can be exceeded by
> a startup every hour surprisingly quickly.

http://www.pcguide.com/ref/hdd/per [...] les-c.html

Well, I'm reading that start/stop cycles are typically in the 30k to
50k range, and that's something I didn't know. I wasn't looking for the
right keywords. One boot per day on a home PC would allow for 109 years
at 40k cycles, which means other components must wear out faster than
bearings! This is the info I needed.

JT