keeping drives cool in a MicroATX case - Storage

This is a discussion on keeping drives cool in a MicroATX case - Storage ; Arno Wagner wrote: > Previously Dan Lenski wrote: >> On Sat, 27 Sep 2008 23:21:12 +0100, Squeeze wrote: > >>> Dan Lenski wrote in >>>> Thanks, Arno. I didn't think of that. Yikes, I'll disable the >>>> spindown. >>> >>> ...

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Thread: keeping drives cool in a MicroATX case

  1. Re: keeping drives cool in a MicroATX case

    Arno Wagner wrote:
    > Previously Dan Lenski wrote:
    >> On Sat, 27 Sep 2008 23:21:12 +0100, Squeeze wrote:

    >
    >>> Dan Lenski wrote in
    >>>> Thanks, Arno. I didn't think of that. Yikes, I'll disable the
    >>>> spindown.
    >>>
    >>> Yeah, obviously spindown can only be set at 1 minute interval and the
    >>> drive will spinup every minute, again and again.

    >
    >> Yeah, I thought that sounded kind of funny, but then I tried it and found
    >> that my drives keep spinning back up... at least they report that they are
    >> in the "Active" rather than "Standby" state.

    >
    >> If I set spindown to 1 minute... they always spin back up within a few
    >> seconds. This is under Ubuntu Linux and I'm not sure what the cause is.
    >> Haven't had time to track it down yet :-(

    >
    > Ah, for Linux, you may want a laptop distribution or maybe
    > embedded distribution that minimizes disk access. There may
    > also be a setting in Ubuntu that allows it. One thing
    > is running swapless or with swap in RAM. Another is not
    > updating last access time-stamps on disk. The buffer flush
    > time can also be modified.
    >
    > There are additional tricks to keep disks accesses that actually
    > involve the disk (and not just the buffer-cache) to a minimum.
    >
    > Arno


    Take a look at linux/Documentation/laptops/laptop-mode.txt, or google
    for something like "linux laptop mode". It's a script that sets the VM
    system to reduce paging and remount disks with noatime.

    Jerry

  2. Re: keeping drives cool in a MicroATX case

    On Tue, 30 Sep 2008 21:00:59 +0000, Jerry Peters wrote:
    > Take a look at linux/Documentation/laptops/laptop-mode.txt, or google
    > for something like "linux laptop mode". It's a script that sets the VM
    > system to reduce paging and remount disks with noatime.
    >
    > Jerry


    Wow... it works! My drives actually spin down now. Cool. But they also
    take 3-4 seconds to spin-up, and it's surprisingly audible. I'll have to
    tweak this a bit.

    Thanks for the tip!

    Dan

  3. Re: keeping drives cool in a MicroATX case

    Arno Wagner wrote:
    > Previously Tom Stephenson wrote:
    >> Drives aren't all the same but universally it's better to keep them
    >> cool. Most drives have a max temperature of 55C. Doesn't mean they will
    >> fail if there is some short term problem and they go higher than 55 but
    >> running then for an extended period beyond 40 isn't a good idea.

    >
    > I have seen immediate failures in the temperature
    > range 70-75C. The drives worked again after cooled down.
    > I agree that <= 40C in normal operation is a good
    > rule of thumb.
    >
    >> Generally, more airflow is better. But be careful about the fan(s). If
    >> you run case fans at a full 12V you get maximum performance but minimum
    >> [fan] life.

    >
    > refer to the fan datasheet for that. there are fans out there
    > that get >100.000 h lifetime under full speed, e.g. by SmattCooler
    > and Enermax. They are a bit more expensive though.
    >

    I find that fans don't always perform to the datasheet spec (especially
    where the MTBF spec is concerned). So I normally want to use a high
    quality mainstream fan supplier but even the best of them will have
    issues from time to time. Spin it down a bit and the life of the fan is
    greatly extended. BTW, fans don't like to be in high temperature
    environments either. The MTBF is derated significantly as the
    temperature goes up. Same with power supplies.


    >> I prefer bigger fans turning slower. Fans running high speed
    >> provide more air but also vibration and hard drives are *very* sensitive
    >> to vibration (some drives more than others).

    >
    > I have never had trouible with a HDD from fan vibration. Should
    > mot be an issue today, unless you have a very flimsy case.


    I have had tons of trouble with drives and vibration. Consider the
    environment of the hot swap drive in a server. The drive is in a
    removable mount. It must be secure yet be able to move when the lever
    has been activated. And normally there are multiple drives mounted
    adjacent to one another. In that environment the spinning mass of a
    drive can easily impact the performance of the adjacent drive just as
    the fans that are hard mounted in the chassis. The chassis and the drive
    carrier have to be very carefully designed to avoid issues with drives
    being impacted by vibration.

    Now you may have had trouble with drives being influenced by vibration
    and not know it. Drives make errors when they read the data from the
    media. There are sufficient ECC bits encoded into the record to correct
    the data as it is read from the media. But when the data is so badly
    scrambled the data cannot be corrected by the ECC logic the drive has to
    do a re-read. That slows performance cause you have to take another
    revolution to fetch the data. Will the data come out OK the second time
    it is read? Maybe, maybe not. What about the third time? How many times
    will the drive read the data before it gives up and declares an error is
    a feature of that individual drive design (firmware on the drive). But
    the drive may take many many retry events before it declares a sector to
    be probationary. (pending sector).

    When I evaluate the performance of a drive I read the entire surface of
    the drive block by block and measure the time it takes to retrieve the
    block. I have my own code that I use for this purpose but there are
    commercial software packages that do the same thing.

    Many performance issues can be identified as vibration issues at the source.

    Scan the data from the drive while mounted in the chassis. Scan the data
    again from the same drive while mounted externally on a very heavy mass
    not connected to the chassis. Compare the read performance. The delta in
    the numbers will the the contribution of the chassis (vibration mostly
    but temperature as well).

    A good chassis design and a good hard drive will have near identical
    performance. But I have seen combinations where the performance is off
    by 20 - 30 percent. Those products never were released to production.

    >
    >> I generally mount a larger fan in front of the drive cage and spin it at
    >> some slower speed to get good airflow across the surface of the drive.

    >
    >> Some chassis designers provide a rubber isolation gasket for the fan.
    >> That's really important to minimize vibration being transmitted to the
    >> drive thru the chassis.

    >
    >> Also FWIW, newer drives consume less power. Much less. And if power
    >> consumption is really important to you WD has a 'green' drive that cuts
    >> way down on power (and performance) by turning 5400 RPM and slowing the
    >> seek rate.

    >
    > Hitachi also has a low power line and normal Samsungs asre also
    > pretty close to low power. In addition, if performance is less
    > of an issue, 2.5" notebook drives are an option. Most are at <2W
    > under load, whioch puts them at about 20-30% power of even the
    > low-power 3.5" drives.
    >
    > Arno


    My experience is with enterprise class drives from WD, Hitachi and
    Seagate. All three are very good at what they do. I understand that the
    new Sammy drives are very good as well.

    Things are going to get tough in the hard drive environment because of
    the SSD products coming our way. As the capacity and price features
    improve, the SSD will begin to impact the hard drive business.

    Tom S.

  4. Re: keeping drives cool in a MicroATX case

    Tom Stephenson wrote in news:i6NEk.3597$cs4.2724@newsfe01.iad
    > Arno Wagner wrote:
    > > Previously Tom Stephenson wrote:
    > > > Drives aren't all the same but universally it's better to keep them
    > > > cool. Most drives have a max temperature of 55C. Doesn't mean they will
    > > > fail if there is some short term problem and they go higher than 55 but
    > > > running then for an extended period beyond 40 isn't a good idea.

    > >
    > > I have seen immediate failures in the temperature
    > > range 70-75C. The drives worked again after cooled down.
    > > I agree that <= 40C in normal operation is a good
    > > rule of thumb.
    > >
    > > > Generally, more airflow is better. But be careful about the fan(s). If
    > > > you run case fans at a full 12V you get maximum performance but minimum
    > > > [fan] life.

    > >
    > > refer to the fan datasheet for that. there are fans out there
    > > that get >100.000 h lifetime under full speed, e.g. by SmattCooler
    > > and Enermax. They are a bit more expensive though.
    > >

    > I find that fans don't always perform to the datasheet spec (especially
    > where the MTBF spec is concerned). So I normally want to use a high
    > quality mainstream fan supplier but even the best of them will have
    > issues from time to time. Spin it down a bit and the life of the fan is
    > greatly extended. BTW, fans don't like to be in high temperature
    > environments either. The MTBF is derated significantly as the
    > temperature goes up. Same with power supplies.
    >
    >
    > > > I prefer bigger fans turning slower. Fans running high speed
    > > > provide more air but also vibration and hard drives are *very* sensitive
    > > > to vibration (some drives more than others).

    > >
    > > I have never had trouible with a HDD from fan vibration. Should
    > > mot be an issue today, unless you have a very flimsy case.

    >
    > I have had tons of trouble with drives and vibration. Consider the
    > environment of the hot swap drive in a server. The drive is in a
    > removable mount. It must be secure yet be able to move when the lever
    > has been activated. And normally there are multiple drives mounted
    > adjacent to one another. In that environment the spinning mass of a
    > drive can easily impact the performance of the adjacent drive just as
    > the fans that are hard mounted in the chassis. The chassis and the drive
    > carrier have to be very carefully designed to avoid issues with drives
    > being impacted by vibration.
    >
    > Now you may have had trouble with drives being influenced by vibration
    > and not know it. Drives make errors when they read the data from the
    > media. There are sufficient ECC bits encoded into the record to correct
    > the data as it is read from the media. But when the data is so badly
    > scrambled the data cannot be corrected by the ECC logic the drive has to
    > do a re-read. That slows performance cause you have to take another
    > revolution to fetch the data. Will the data come out OK the second time
    > it is read? Maybe, maybe not. What about the third time?


    > How many times will the drive read the data before it gives up and de-
    > clares an error is a feature of that individual drive design (firmware on
    > the drive).


    And then the driver takes over making it do that all over again, several times.


  5. Re: keeping drives cool in a MicroATX case

    Previously Tom Stephenson wrote:
    > Arno Wagner wrote:
    >> Previously Tom Stephenson wrote:
    >>> Drives aren't all the same but universally it's better to keep them
    >>> cool. Most drives have a max temperature of 55C. Doesn't mean they will
    >>> fail if there is some short term problem and they go higher than 55 but
    >>> running then for an extended period beyond 40 isn't a good idea.

    >>
    >> I have seen immediate failures in the temperature
    >> range 70-75C. The drives worked again after cooled down.
    >> I agree that <= 40C in normal operation is a good
    >> rule of thumb.
    >>
    >>> Generally, more airflow is better. But be careful about the fan(s). If
    >>> you run case fans at a full 12V you get maximum performance but minimum
    >>> [fan] life.

    >>
    >> refer to the fan datasheet for that. there are fans out there
    >> that get >100.000 h lifetime under full speed, e.g. by SmattCooler
    >> and Enermax. They are a bit more expensive though.
    >>


    > I find that fans don't always perform to the datasheet spec (especially
    > where the MTBF spec is concerned).


    MTBF has no relation to lifetime, or rather the lifetime
    is where the MTBF gives the failure probability. So MTBF is
    not at all for wear and tear but for "random" failures.

    > So I normally want to use a high
    > quality mainstream fan supplier but even the best of them will have
    > issues from time to time. Spin it down a bit and the life of the fan is
    > greatly extended. BTW, fans don't like to be in high temperature
    > environments either. The MTBF is derated significantly as the
    > temperature goes up. Same with power supplies.


    The enermax ones have 100'000h lifetime at 80C. Smartcooler have
    100'000h at 40C, if I remember correctly. Things like NMB
    not high quality.

    >>> I prefer bigger fans turning slower. Fans running high speed
    >>> provide more air but also vibration and hard drives are *very* sensitive
    >>> to vibration (some drives more than others).

    >>
    >> I have never had trouible with a HDD from fan vibration. Should
    >> mot be an issue today, unless you have a very flimsy case.


    > I have had tons of trouble with drives and vibration. Consider the
    > environment of the hot swap drive in a server. The drive is in a
    > removable mount. It must be secure yet be able to move when the lever
    > has been activated. And normally there are multiple drives mounted
    > adjacent to one another. In that environment the spinning mass of a
    > drive can easily impact the performance of the adjacent drive just as
    > the fans that are hard mounted in the chassis. The chassis and the drive
    > carrier have to be very carefully designed to avoid issues with drives
    > being impacted by vibration.


    I have had up to 12 Disks in one server tower. Never had an issue.

    > Now you may have had trouble with drives being influenced by vibration
    > and not know it. Drives make errors when they read the data from the
    > media. There are sufficient ECC bits encoded into the record to correct
    > the data as it is read from the media. But when the data is so badly
    > scrambled the data cannot be corrected by the ECC logic the drive has to
    > do a re-read. That slows performance cause you have to take another
    > revolution to fetch the data. Will the data come out OK the second time
    > it is read? Maybe, maybe not. What about the third time? How many times
    > will the drive read the data before it gives up and declares an error is
    > a feature of that individual drive design (firmware on the drive). But
    > the drive may take many many retry events before it declares a sector to
    > be probationary. (pending sector).


    Sorry, no. Not with said server or the 22 attached cluster nodes
    (whith 2-3 disk each in one disk cage) during 3 years.

    > When I evaluate the performance of a drive I read the entire surface of
    > the drive block by block and measure the time it takes to retrieve the
    > block. I have my own code that I use for this purpose but there are
    > commercial software packages that do the same thing.


    I have used the same approach before the smartmontools for linux
    began to work well. No observations with regard to vibration.

    > Many performance issues can be identified as vibration issues at the source.


    > Scan the data from the drive while mounted in the chassis. Scan the data
    > again from the same drive while mounted externally on a very heavy mass
    > not connected to the chassis. Compare the read performance. The delta in
    > the numbers will the the contribution of the chassis (vibration mostly
    > but temperature as well).


    > A good chassis design and a good hard drive will have near identical
    > performance. But I have seen combinations where the performance is off
    > by 20 - 30 percent. Those products never were released to production.


    Aha. Maybe I just bought too good quality to observe the effect.
    But then, many of the disks were Maxtors.

    >>
    >>> I generally mount a larger fan in front of the drive cage and spin it at
    >>> some slower speed to get good airflow across the surface of the drive.

    >>
    >>> Some chassis designers provide a rubber isolation gasket for the fan.
    >>> That's really important to minimize vibration being transmitted to the
    >>> drive thru the chassis.

    >>
    >>> Also FWIW, newer drives consume less power. Much less. And if power
    >>> consumption is really important to you WD has a 'green' drive that cuts
    >>> way down on power (and performance) by turning 5400 RPM and slowing the
    >>> seek rate.

    >>
    >> Hitachi also has a low power line and normal Samsungs asre also
    >> pretty close to low power. In addition, if performance is less
    >> of an issue, 2.5" notebook drives are an option. Most are at <2W
    >> under load, whioch puts them at about 20-30% power of even the
    >> low-power 3.5" drives.
    >>
    >> Arno


    > My experience is with enterprise class drives from WD, Hitachi and
    > Seagate. All three are very good at what they do. I understand that the
    > new Sammy drives are very good as well.


    > Things are going to get tough in the hard drive environment because of
    > the SSD products coming our way. As the capacity and price features
    > improve, the SSD will begin to impact the hard drive business.


    Not for many apps. SSDs are far from competitive, if seek time
    and throughput is secondary. And they will remain more expensive
    than HDDs for quite some time. Might even be for decades.

    Arno

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