Very slow copying data from RAID 1 array. - Storage

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  1. Very slow copying data from RAID 1 array.

    Hi

    I have a 500GB RAID1 array using brand new Western Digital drives and the
    Sil 3114 chipset on my ASUS A8N-SLI Premium system board.

    I use the RAID to store partition backup image files which are split into
    multiple 2GB segments. The backup segments total approx 70Gb.

    Each week I copy the image files to a removable hard drive which usually
    takes approx 25-30mins.

    However today after selecting all the segments (77GB Total) and beginning
    the copy,
    Windows is estimating over 200 minutes for the copying!

    I had similar trouble a few months ago so ran a disc check on the RAID array
    which took over 30hrs to complete! It seemed to fix whatever errors it
    found as since then it ran normally taking approx 25-30mins to copy the
    files.

    However today the same lengthy copying problem has recurred.

    Any idea what might cause this?

    Right now I'm thinking I'll need to reformat the drives but I'll have to buy
    another 500GB drive to painstakingly copy all the data off the RAID array
    first! Bummer!

    Thanks for any info.

    Ian









  2. Re: Very slow copying data from RAID 1 array.

    Previously Ian R wrote:
    > Hi


    > I have a 500GB RAID1 array using brand new Western Digital drives and the
    > Sil 3114 chipset on my ASUS A8N-SLI Premium system board.


    > I use the RAID to store partition backup image files which are split into
    > multiple 2GB segments. The backup segments total approx 70Gb.


    > Each week I copy the image files to a removable hard drive which usually
    > takes approx 25-30mins.


    > However today after selecting all the segments (77GB Total) and beginning
    > the copy,
    > Windows is estimating over 200 minutes for the copying!


    > I had similar trouble a few months ago so ran a disc check on the RAID array
    > which took over 30hrs to complete! It seemed to fix whatever errors it
    > found as since then it ran normally taking approx 25-30mins to copy the
    > files.


    > However today the same lengthy copying problem has recurred.


    > Any idea what might cause this?


    > Right now I'm thinking I'll need to reformat the drives but I'll have to buy
    > another 500GB drive to painstakingly copy all the data off the RAID array
    > first! Bummer!


    > Thanks for any info.


    > Ian


    30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    is about 6MB/s. Quite slow. May be PIO instead of DMA
    on a disk (bad cabeling), may be excessive fragmentation.
    May also be bad sectors or other disk issues.

    Do not replace the disks before you have have diagnised the
    problem. At the moment it need not be the disks themselves.

    Arno








  3. Re: Very slow copying data from RAID 1 array.

    Arno Wagner wrote:
    > Previously Ian R wrote:
    >> Hi

    >
    >> I have a 500GB RAID1 array using brand new Western Digital drives
    >> and the Sil 3114 chipset on my ASUS A8N-SLI Premium system board.

    >
    >> I use the RAID to store partition backup image files which are split
    >> into multiple 2GB segments. The backup segments total approx 70Gb.

    >
    >> Each week I copy the image files to a removable hard drive which
    >> usually takes approx 25-30mins.

    >
    >> However today after selecting all the segments (77GB Total) and
    >> beginning the copy,
    >> Windows is estimating over 200 minutes for the copying!

    >
    >> I had similar trouble a few months ago so ran a disc check on the
    >> RAID array which took over 30hrs to complete! It seemed to fix
    >> whatever errors it found as since then it ran normally taking approx
    >> 25-30mins to copy the files.

    >
    >> However today the same lengthy copying problem has recurred.

    >
    >> Any idea what might cause this?

    >
    >> Right now I'm thinking I'll need to reformat the drives but I'll
    >> have to buy another 500GB drive to painstakingly copy all the data
    >> off the RAID array first! Bummer!


    > 30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    > is about 6MB/s. Quite slow. May be PIO instead of DMA on a disk


    Yes.

    > (bad cabeling),


    Or something else turned the DMA off.

    > may be excessive fragmentation.


    Nope, you wont get that dramatic a result from that.

    > May also be bad sectors or other disk issues.


    Yep. And the best way to check for that is the SMART report,
    after breaking the RAID array if necessary to do that.

    > Do not replace the disks before you have have diagnised the
    > problem. At the moment it need not be the disks themselves.




  4. Re: Very slow copying data from RAID 1 array.


    "Arno Wagner" wrote in message
    news:5rdl3gFskv5eU1@mid.individual.net...
    > Previously Ian R wrote:
    >> Hi

    >
    >> I have a 500GB RAID1 array using brand new Western Digital drives and the
    >> Sil 3114 chipset on my ASUS A8N-SLI Premium system board.

    >
    >> I use the RAID to store partition backup image files which are split into
    >> multiple 2GB segments. The backup segments total approx 70Gb.

    >
    >> Each week I copy the image files to a removable hard drive which usually
    >> takes approx 25-30mins.

    >
    >> However today after selecting all the segments (77GB Total) and beginning
    >> the copy,
    >> Windows is estimating over 200 minutes for the copying!

    >
    >> I had similar trouble a few months ago so ran a disc check on the RAID
    >> array
    >> which took over 30hrs to complete! It seemed to fix whatever errors it
    >> found as since then it ran normally taking approx 25-30mins to copy the
    >> files.

    >
    >> However today the same lengthy copying problem has recurred.

    >
    >> Any idea what might cause this?

    >
    >> Right now I'm thinking I'll need to reformat the drives but I'll have to
    >> buy
    >> another 500GB drive to painstakingly copy all the data off the RAID array
    >> first! Bummer!

    >
    >> Thanks for any info.

    >
    >> Ian

    >
    > 30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    > is about 6MB/s. Quite slow. May be PIO instead of DMA
    > on a disk (bad cabeling), may be excessive fragmentation.
    > May also be bad sectors or other disk issues.
    >
    > Do not replace the disks before you have have diagnised the
    > problem. At the moment it need not be the disks themselves.
    >
    > Arno
    >



    Hi Arno

    Thanks for replying.

    Ive checked all the settings for the disk drives, SATA controller and RAID
    controller in device manager as well as disc settings in disk management but
    I cant see anywhere to check or alter the transfer mode to the RAID array.

    I've downloaded and installed the lastest WD Data Lifeguard Tools but it
    didnt report any problems and it seems pretty sparse in that it doesnt seem
    to offer any diagnostic utilities.

    Are there third party utilities I can run which can check the drives while
    they are still part of the RAID?

    I'm *slowly* moving stuff off the RAID - buring to DVD-R but its painfully
    slow. Ive got an 18x DVD burner and with Verbatim discs I can usually burn
    at 18x. But tonight Nero says.. "can only write at 4x because the speed of
    the source data is too slow".

    As if I didnt know!

    Cheers

    Ian







  5. Re: Very slow copying data from RAID 1 array.

    Previously 231 <231@alok.com> wrote:
    > Arno Wagner wrote:
    >> Previously Ian R wrote:
    >>> Hi

    >>
    >>> I have a 500GB RAID1 array using brand new Western Digital drives
    >>> and the Sil 3114 chipset on my ASUS A8N-SLI Premium system board.

    >>
    >>> I use the RAID to store partition backup image files which are split
    >>> into multiple 2GB segments. The backup segments total approx 70Gb.

    >>
    >>> Each week I copy the image files to a removable hard drive which
    >>> usually takes approx 25-30mins.

    >>
    >>> However today after selecting all the segments (77GB Total) and
    >>> beginning the copy,
    >>> Windows is estimating over 200 minutes for the copying!

    >>
    >>> I had similar trouble a few months ago so ran a disc check on the
    >>> RAID array which took over 30hrs to complete! It seemed to fix
    >>> whatever errors it found as since then it ran normally taking approx
    >>> 25-30mins to copy the files.

    >>
    >>> However today the same lengthy copying problem has recurred.

    >>
    >>> Any idea what might cause this?

    >>
    >>> Right now I'm thinking I'll need to reformat the drives but I'll
    >>> have to buy another 500GB drive to painstakingly copy all the data
    >>> off the RAID array first! Bummer!


    >> 30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    >> is about 6MB/s. Quite slow. May be PIO instead of DMA on a disk


    > Yes.


    >> (bad cabeling),


    > Or something else turned the DMA off.


    >> may be excessive fragmentation.


    > Nope, you wont get that dramatic a result from that.


    Oh, yes. You can get even worse. I have seen it. Remember that
    this is an average over 77GB.

    >> May also be bad sectors or other disk issues.


    > Yep. And the best way to check for that is the SMART report,
    > after breaking the RAID array if necessary to do that.


    Actually the way to do this is to attach the disks to a different
    controller and never acess them in R/W mode. E.g. Knoppix
    can help here.

    Arno



  6. Re: Very slow copying data from RAID 1 array.

    Previously Ian R wrote:

    > "Arno Wagner" wrote in message
    > news:5rdl3gFskv5eU1@mid.individual.net...
    >> Previously Ian R wrote:
    >>> Hi

    >>
    >>> I have a 500GB RAID1 array using brand new Western Digital drives and the
    >>> Sil 3114 chipset on my ASUS A8N-SLI Premium system board.

    >>
    >>> I use the RAID to store partition backup image files which are split into
    >>> multiple 2GB segments. The backup segments total approx 70Gb.

    >>
    >>> Each week I copy the image files to a removable hard drive which usually
    >>> takes approx 25-30mins.

    >>
    >>> However today after selecting all the segments (77GB Total) and beginning
    >>> the copy,
    >>> Windows is estimating over 200 minutes for the copying!

    >>
    >>> I had similar trouble a few months ago so ran a disc check on the RAID
    >>> array
    >>> which took over 30hrs to complete! It seemed to fix whatever errors it
    >>> found as since then it ran normally taking approx 25-30mins to copy the
    >>> files.

    >>
    >>> However today the same lengthy copying problem has recurred.

    >>
    >>> Any idea what might cause this?

    >>
    >>> Right now I'm thinking I'll need to reformat the drives but I'll have to
    >>> buy
    >>> another 500GB drive to painstakingly copy all the data off the RAID array
    >>> first! Bummer!

    >>
    >>> Thanks for any info.

    >>
    >>> Ian

    >>
    >> 30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    >> is about 6MB/s. Quite slow. May be PIO instead of DMA
    >> on a disk (bad cabeling), may be excessive fragmentation.
    >> May also be bad sectors or other disk issues.
    >>
    >> Do not replace the disks before you have have diagnised the
    >> problem. At the moment it need not be the disks themselves.
    >>
    >> Arno
    >>



    > Hi Arno


    > Thanks for replying.


    > Ive checked all the settings for the disk drives, SATA controller and RAID
    > controller in device manager as well as disc settings in disk management but
    > I cant see anywhere to check or alter the transfer mode to the RAID array.


    > I've downloaded and installed the lastest WD Data Lifeguard Tools but it
    > didnt report any problems and it seems pretty sparse in that it doesnt seem
    > to offer any diagnostic utilities.


    > Are there third party utilities I can run which can check the drives while
    > they are still part of the RAID?


    You can remove both disks, attach each one to a different
    controller and use a Knoppix CD only Linux to get their SMART
    status, and in addition run a long SMART selftest. The tool for
    this is smartctl. Knoppix mounts the disks readonly, so they will
    form a valid RAID again, when connected back to the RAID controller.

    > I'm *slowly* moving stuff off the RAID - buring to DVD-R but its
    > painfully slow. Ive got an 18x DVD burner and with Verbatim discs I
    > can usually burn at 18x. But tonight Nero says.. "can only write at
    > 4x because the speed of the source data is too slow".


    > As if I didnt know!


    Hm. Maybe get a cheap external USB HDD and move everytginh there?
    You could do this overnight and unattended.

    Arno






  7. Re: Very slow copying data from RAID 1 array.

    Arno Wagner wrote:
    > Previously 231 <231@alok.com> wrote:
    >> Arno Wagner wrote:
    >>> Previously Ian R wrote:
    >>>> Hi
    >>>
    >>>> I have a 500GB RAID1 array using brand new Western Digital drives
    >>>> and the Sil 3114 chipset on my ASUS A8N-SLI Premium system board.
    >>>
    >>>> I use the RAID to store partition backup image files which are
    >>>> split into multiple 2GB segments. The backup segments total approx
    >>>> 70Gb.
    >>>
    >>>> Each week I copy the image files to a removable hard drive which
    >>>> usually takes approx 25-30mins.
    >>>
    >>>> However today after selecting all the segments (77GB Total) and
    >>>> beginning the copy,
    >>>> Windows is estimating over 200 minutes for the copying!
    >>>
    >>>> I had similar trouble a few months ago so ran a disc check on the
    >>>> RAID array which took over 30hrs to complete! It seemed to fix
    >>>> whatever errors it found as since then it ran normally taking
    >>>> approx 25-30mins to copy the files.
    >>>
    >>>> However today the same lengthy copying problem has recurred.
    >>>
    >>>> Any idea what might cause this?
    >>>
    >>>> Right now I'm thinking I'll need to reformat the drives but I'll
    >>>> have to buy another 500GB drive to painstakingly copy all the data
    >>>> off the RAID array first! Bummer!

    >
    >>> 30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    >>> is about 6MB/s. Quite slow. May be PIO instead of DMA on a disk

    >
    >> Yes.

    >
    >>> (bad cabeling),

    >
    >> Or something else turned the DMA off.

    >
    >>> may be excessive fragmentation.

    >
    >> Nope, you wont get that dramatic a result from that.


    > Oh, yes.


    Nope.

    > You can get even worse.


    Nope.

    > I have seen it.


    No you havent.

    > Remember that this is an average over 77GB.


    You cant get a 7/1 reduction in thruput due to excessive fragmentation.

    The size is irrelevant to that.

    >>> May also be bad sectors or other disk issues.


    >> Yep. And the best way to check for that is the SMART report,
    >> after breaking the RAID array if necessary to do that.


    > Actually the way to do this is to attach the disks to a
    > different controller and never acess them in R/W mode.


    What I said in different words.

    > E.g. Knoppix can help here.




  8. Re: Very slow copying data from RAID 1 array.

    Previously 231 <231@alok.com> wrote:
    > Arno Wagner wrote:
    >> Previously 231 <231@alok.com> wrote:
    >>> Arno Wagner wrote:
    >>>> Previously Ian R wrote:
    >>>>> Hi
    >>>>
    >>>>> I have a 500GB RAID1 array using brand new Western Digital drives
    >>>>> and the Sil 3114 chipset on my ASUS A8N-SLI Premium system board.
    >>>>
    >>>>> I use the RAID to store partition backup image files which are
    >>>>> split into multiple 2GB segments. The backup segments total approx
    >>>>> 70Gb.
    >>>>
    >>>>> Each week I copy the image files to a removable hard drive which
    >>>>> usually takes approx 25-30mins.
    >>>>
    >>>>> However today after selecting all the segments (77GB Total) and
    >>>>> beginning the copy,
    >>>>> Windows is estimating over 200 minutes for the copying!
    >>>>
    >>>>> I had similar trouble a few months ago so ran a disc check on the
    >>>>> RAID array which took over 30hrs to complete! It seemed to fix
    >>>>> whatever errors it found as since then it ran normally taking
    >>>>> approx 25-30mins to copy the files.
    >>>>
    >>>>> However today the same lengthy copying problem has recurred.
    >>>>
    >>>>> Any idea what might cause this?
    >>>>
    >>>>> Right now I'm thinking I'll need to reformat the drives but I'll
    >>>>> have to buy another 500GB drive to painstakingly copy all the data
    >>>>> off the RAID array first! Bummer!

    >>
    >>>> 30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    >>>> is about 6MB/s. Quite slow. May be PIO instead of DMA on a disk

    >>
    >>> Yes.

    >>
    >>>> (bad cabeling),

    >>
    >>> Or something else turned the DMA off.

    >>
    >>>> may be excessive fragmentation.

    >>
    >>> Nope, you wont get that dramatic a result from that.


    >> Oh, yes.


    > Nope.


    >> You can get even worse.


    > Nope.


    >> I have seen it.


    > No you havent.


    >> Remember that this is an average over 77GB.


    > You cant get a 7/1 reduction in thruput due to excessive fragmentation.


    > The size is irrelevant to that.


    You have no clue what you are talking about, obviously. The worst
    case, and it can be reached in practice, is one seek per cluster. If
    we assume 16kB clusters and a 7200rpm disk with 10ms seek time and 4ms
    average latency, that comes down to just over 1MB/s. That is without
    any accesses for the management information and time to actually read
    anything.

    Arno

  9. Re: Very slow copying data from RAID 1 array.

    "Arno Wagner" wrote in message news:5rgs42F13kjkiU1@mid.individual.net...
    >>>
    >>>>> may be excessive fragmentation.
    >>>
    >>>> Nope, you wont get that dramatic a result from that.

    >
    >>> Oh, yes.

    >
    >> Nope.

    >
    >>> You can get even worse.

    >
    >> Nope.

    >
    >>> I have seen it.

    >
    >> No you havent.

    >
    >>> Remember that this is an average over 77GB.

    >
    >> You cant get a 7/1 reduction in thruput due to excessive fragmentation.

    >
    >> The size is irrelevant to that.

    >
    > You have no clue what you are talking about, obviously. The worst
    > case, and it can be reached in practice, is one seek per cluster. If
    > we assume 16kB clusters and a 7200rpm disk with 10ms seek time and 4ms
    > average latency, that comes down to just over 1MB/s. That is without
    > any accesses for the management information and time to actually read
    > anything.
    >

    You have no real world experience. Free clusters come in runs, not randomly scattered.

  10. Re: Very slow copying data from RAID 1 array.

    Arno Wagner wrote:
    > Previously 231 <231@alok.com> wrote:
    >> Arno Wagner wrote:
    >>> Previously 231 <231@alok.com> wrote:
    >>>> Arno Wagner wrote:
    >>>>> Previously Ian R wrote:
    >>>>>> Hi
    >>>>>
    >>>>>> I have a 500GB RAID1 array using brand new Western Digital drives
    >>>>>> and the Sil 3114 chipset on my ASUS A8N-SLI Premium system board.
    >>>>>
    >>>>>> I use the RAID to store partition backup image files which are
    >>>>>> split into multiple 2GB segments. The backup segments total
    >>>>>> approx 70Gb.
    >>>>>
    >>>>>> Each week I copy the image files to a removable hard drive which
    >>>>>> usually takes approx 25-30mins.
    >>>>>
    >>>>>> However today after selecting all the segments (77GB Total) and
    >>>>>> beginning the copy,
    >>>>>> Windows is estimating over 200 minutes for the copying!
    >>>>>
    >>>>>> I had similar trouble a few months ago so ran a disc check on the
    >>>>>> RAID array which took over 30hrs to complete! It seemed to fix
    >>>>>> whatever errors it found as since then it ran normally taking
    >>>>>> approx 25-30mins to copy the files.
    >>>>>
    >>>>>> However today the same lengthy copying problem has recurred.
    >>>>>
    >>>>>> Any idea what might cause this?
    >>>>>
    >>>>>> Right now I'm thinking I'll need to reformat the drives but I'll
    >>>>>> have to buy another 500GB drive to painstakingly copy all the
    >>>>>> data off the RAID array first! Bummer!
    >>>
    >>>>> 30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    >>>>> is about 6MB/s. Quite slow. May be PIO instead of DMA on a disk
    >>>
    >>>> Yes.
    >>>
    >>>>> (bad cabeling),
    >>>
    >>>> Or something else turned the DMA off.
    >>>
    >>>>> may be excessive fragmentation.
    >>>
    >>>> Nope, you wont get that dramatic a result from that.

    >
    >>> Oh, yes.

    >
    >> Nope.

    >
    >>> You can get even worse.

    >
    >> Nope.

    >
    >>> I have seen it.

    >
    >> No you havent.

    >
    >>> Remember that this is an average over 77GB.

    >
    >> You cant get a 7/1 reduction in thruput due to excessive
    >> fragmentation.

    >
    >> The size is irrelevant to that.


    > You have no clue what you are talking about, obviously.


    We'll see...

    > The worst case, and it can be reached in practice, is one seek per cluster.


    That never ever happens in practice.

    > If we assume 16kB clusters and a 7200rpm disk with 10ms seek
    > time and 4ms average latency, that comes down to just over 1MB/s.


    Nope.

    > That is without any accesses for the management
    > information and time to actually read anything.


    Wrong, as always.



  11. Re: Very slow copying data from RAID 1 array.

    Previously 231 <231@alok.com> wrote:
    > Arno Wagner wrote:
    >> Previously 231 <231@alok.com> wrote:
    >>> Arno Wagner wrote:
    >>>> Previously 231 <231@alok.com> wrote:
    >>>>> Arno Wagner wrote:
    >>>>>> Previously Ian R wrote:
    >>>>>>> Hi
    >>>>>>
    >>>>>>> I have a 500GB RAID1 array using brand new Western Digital drives
    >>>>>>> and the Sil 3114 chipset on my ASUS A8N-SLI Premium system board.
    >>>>>>
    >>>>>>> I use the RAID to store partition backup image files which are
    >>>>>>> split into multiple 2GB segments. The backup segments total
    >>>>>>> approx 70Gb.
    >>>>>>
    >>>>>>> Each week I copy the image files to a removable hard drive which
    >>>>>>> usually takes approx 25-30mins.
    >>>>>>
    >>>>>>> However today after selecting all the segments (77GB Total) and
    >>>>>>> beginning the copy,
    >>>>>>> Windows is estimating over 200 minutes for the copying!
    >>>>>>
    >>>>>>> I had similar trouble a few months ago so ran a disc check on the
    >>>>>>> RAID array which took over 30hrs to complete! It seemed to fix
    >>>>>>> whatever errors it found as since then it ran normally taking
    >>>>>>> approx 25-30mins to copy the files.
    >>>>>>
    >>>>>>> However today the same lengthy copying problem has recurred.
    >>>>>>
    >>>>>>> Any idea what might cause this?
    >>>>>>
    >>>>>>> Right now I'm thinking I'll need to reformat the drives but I'll
    >>>>>>> have to buy another 500GB drive to painstakingly copy all the
    >>>>>>> data off the RAID array first! Bummer!
    >>>>
    >>>>>> 30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    >>>>>> is about 6MB/s. Quite slow. May be PIO instead of DMA on a disk
    >>>>
    >>>>> Yes.
    >>>>
    >>>>>> (bad cabeling),
    >>>>
    >>>>> Or something else turned the DMA off.
    >>>>
    >>>>>> may be excessive fragmentation.
    >>>>
    >>>>> Nope, you wont get that dramatic a result from that.

    >>
    >>>> Oh, yes.

    >>
    >>> Nope.

    >>
    >>>> You can get even worse.

    >>
    >>> Nope.

    >>
    >>>> I have seen it.

    >>
    >>> No you havent.

    >>
    >>>> Remember that this is an average over 77GB.

    >>
    >>> You cant get a 7/1 reduction in thruput due to excessive
    >>> fragmentation.

    >>
    >>> The size is irrelevant to that.


    >> You have no clue what you are talking about, obviously.


    > We'll see...


    >> The worst case, and it can be reached in practice, is one seek per cluster.


    > That never ever happens in practice.


    >> If we assume 16kB clusters and a 7200rpm disk with 10ms seek
    >> time and 4ms average latency, that comes down to just over 1MB/s.


    > Nope.


    >> That is without any accesses for the management
    >> information and time to actually read anything.


    > Wrong, as always.


    Obviously you cannot do basic arithmetric. No use
    arguing with this level of incompetence.

    Arno


  12. Re: Very slow copying data from RAID 1 array.

    > Arno- Hide quoted text -
    >
    > - Show quoted text -


    I think the question of theoretical slowing down due to fragmentation
    is irrelevant. A heavily fragmented drive can be slower, but not by
    much.

    A drive with failing physical sectors, requiring many retries will be
    slow, I think this is were you need to investiagte

    Personally I would advise against doing a backup onto DVDs as they are
    not always 100% reliable. A 500GB drive, as suggested above is simple
    and you are less likely to miss out any files. If you hit a very slow
    part reading your master disk, the DVD copy may fail, but your hard
    drive copy will be fine.


    Michael
    www.cnwrecovery.com

  13. Re: Very slow copying data from RAID 1 array.

    Previously mscotgrove@aol.com wrote:
    >> Arno- Hide quoted text -
    >>
    >> - Show quoted text -


    > I think the question of theoretical slowing down due to fragmentation
    > is irrelevant. A heavily fragmented drive can be slower, but not by
    > much.


    I am just saying that in cetain pathological situations it can
    reach the slow speed stated. It is quite unlikely to happen
    in practice, but the observes problem is as well.

    > A drive with failing physical sectors, requiring many retries will be
    > slow, I think this is were you need to investiagte


    Indeed. A very likely explanation.

    Arno

  14. Re: Very slow copying data from RAID 1 array.

    Arno Wagner wrote:
    > Previously mscotgrove@aol.com wrote:
    >>> Arno- Hide quoted text -
    >>>
    >>> - Show quoted text -

    >
    >> I think the question of theoretical slowing down due to
    >> fragmentation is irrelevant. A heavily fragmented drive can be
    >> slower, but not by much.


    > I am just saying that in cetain pathological
    > situations it can reach the slow speed stated.


    No it cant, because those fantasys never happen in the real world.

    > It is quite unlikely to happen in practice,


    Impossible, actually.

    > but the observes problem is as well.


    Wrong, as always.



  15. Re: Very slow copying data from RAID 1 array.

    Arno Wagner wrote:
    > Previously 231 <231@alok.com> wrote:
    >> Arno Wagner wrote:
    >>> Previously 231 <231@alok.com> wrote:
    >>>> Arno Wagner wrote:
    >>>>> Previously 231 <231@alok.com> wrote:
    >>>>>> Arno Wagner wrote:
    >>>>>>> Previously Ian R wrote:
    >>>>>>>> Hi
    >>>>>>>
    >>>>>>>> I have a 500GB RAID1 array using brand new Western Digital
    >>>>>>>> drives and the Sil 3114 chipset on my ASUS A8N-SLI Premium
    >>>>>>>> system board.
    >>>>>>>
    >>>>>>>> I use the RAID to store partition backup image files which are
    >>>>>>>> split into multiple 2GB segments. The backup segments total
    >>>>>>>> approx 70Gb.
    >>>>>>>
    >>>>>>>> Each week I copy the image files to a removable hard drive
    >>>>>>>> which usually takes approx 25-30mins.
    >>>>>>>
    >>>>>>>> However today after selecting all the segments (77GB Total) and
    >>>>>>>> beginning the copy,
    >>>>>>>> Windows is estimating over 200 minutes for the copying!
    >>>>>>>
    >>>>>>>> I had similar trouble a few months ago so ran a disc check on
    >>>>>>>> the RAID array which took over 30hrs to complete! It seemed
    >>>>>>>> to fix whatever errors it found as since then it ran normally
    >>>>>>>> taking approx 25-30mins to copy the files.
    >>>>>>>
    >>>>>>>> However today the same lengthy copying problem has recurred.
    >>>>>>>
    >>>>>>>> Any idea what might cause this?
    >>>>>>>
    >>>>>>>> Right now I'm thinking I'll need to reformat the drives but
    >>>>>>>> I'll have to buy another 500GB drive to painstakingly copy all
    >>>>>>>> the data off the RAID array first! Bummer!
    >>>>>
    >>>>>>> 30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    >>>>>>> is about 6MB/s. Quite slow. May be PIO instead of DMA on a disk
    >>>>>
    >>>>>> Yes.
    >>>>>
    >>>>>>> (bad cabeling),
    >>>>>
    >>>>>> Or something else turned the DMA off.
    >>>>>
    >>>>>>> may be excessive fragmentation.
    >>>>>
    >>>>>> Nope, you wont get that dramatic a result from that.
    >>>
    >>>>> Oh, yes.
    >>>
    >>>> Nope.
    >>>
    >>>>> You can get even worse.
    >>>
    >>>> Nope.
    >>>
    >>>>> I have seen it.
    >>>
    >>>> No you havent.
    >>>
    >>>>> Remember that this is an average over 77GB.
    >>>
    >>>> You cant get a 7/1 reduction in thruput due to excessive
    >>>> fragmentation.
    >>>
    >>>> The size is irrelevant to that.

    >
    >>> You have no clue what you are talking about, obviously.

    >
    >> We'll see...

    >
    >>> The worst case, and it can be reached in practice, is one seek per
    >>> cluster.

    >
    >> That never ever happens in practice.

    >
    >>> If we assume 16kB clusters and a 7200rpm disk with 10ms seek
    >>> time and 4ms average latency, that comes down to just over 1MB/s.

    >
    >> Nope.

    >
    >>> That is without any accesses for the management
    >>> information and time to actually read anything.

    >
    >> Wrong, as always.

    >
    > Obviously you cannot do basic arithmetric.


    Obviously you have never ever been able to bull**** your way out of a wet paper bag.

    > No use arguing with this level of incompetence.


    Your pathetic excuse for bull**** in spades.



  16. Re: Very slow copying data from RAID 1 array.

    Arno Wagner wrote in news:5rdl3gFskv5eU1@mid.individual.net
    > Previously Ian R wrote:
    > > Hi

    >
    > > I have a 500GB RAID1 array using brand new Western Digital drives and the
    > > Sil 3114 chipset on my ASUS A8N-SLI Premium system board.

    >
    > > I use the RAID to store partition backup image files which are split into
    > > multiple 2GB segments. The backup segments total approx 70Gb.

    >
    > > Each week I copy the image files to a removable hard drive which usually
    > > takes approx 25-30mins.

    >
    > > However today after selecting all the segments (77GB Total) and beginning
    > > the copy,
    > > Windows is estimating over 200 minutes for the copying!

    >
    > > I had similar trouble a few months ago so ran a disc check on the RAID array
    > > which took over 30hrs to complete! It seemed to fix whatever errors it
    > > found as since then it ran normally taking approx 25-30mins to copy the
    > > files.

    >
    > > However today the same lengthy copying problem has recurred.

    >
    > > Any idea what might cause this?

    >
    > > Right now I'm thinking I'll need to reformat the drives but I'll have to buy
    > > another 500GB drive to painstakingly copy all the data off the RAID array
    > > first! Bummer!

    >
    > > Thanks for any info.

    >
    > > Ian


    > 30 min for 77GB is about 42MB/s. That is pretty good.


    > 200 min is about 6MB/s. Quite slow.


    Depends on how crowded the source and/or destination directories are.

    > May be PIO instead of DMA on a disk (bad cabeling),


    PIO on SATA, babblebot? Have you fallen off your beliefs now.

    > may be excessive fragmentation.
    > May also be bad sectors


    May be Gods hand too, right babblebot?

    > or other disk issues.


    Yep, that should about sum it up.

    >
    > Do not replace the disks before you have have diagnised the
    > problem. At the moment it need not be the disks themselves.
    >
    > Arno


  17. Re: Very slow copying data from RAID 1 array.

    Arno Wagner wrote in news:5rfunnF1420k2U1@mid.individual.net
    > Previously 231 <231@alok.com> wrote:
    > > Arno Wagner wrote:
    > > > Previously Ian R wrote:
    > > > > Hi
    > > >
    > > > > I have a 500GB RAID1 array using brand new Western Digital drives
    > > > > and the Sil 3114 chipset on my ASUS A8N-SLI Premium system board.
    > > >
    > > > > I use the RAID to store partition backup image files which are split
    > > > > into multiple 2GB segments. The backup segments total approx 70Gb.
    > > >
    > > > > Each week I copy the image files to a removable hard drive which
    > > > > usually takes approx 25-30mins.
    > > >
    > > > > However today after selecting all the segments (77GB Total) and
    > > > > beginning the copy,


    > > > > Windows is estimating over 200 minutes for the copying!


    The key word here is "estimating".

    > > >
    > > > > I had similar trouble a few months ago so ran a disc check on the
    > > > > RAID array which took over 30hrs to complete! It seemed to fix
    > > > > whatever errors it found as since then it ran normally taking approx
    > > > > 25-30mins to copy the files.
    > > >
    > > > > However today the same lengthy copying problem has recurred.
    > > >
    > > > > Any idea what might cause this?
    > > >
    > > > > Right now I'm thinking I'll need to reformat the drives but I'll
    > > > > have to buy another 500GB drive to painstakingly copy all the data
    > > > > off the RAID array first! Bummer!

    >
    > > > 30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    > > > is about 6MB/s. Quite slow. May be PIO instead of DMA on a disk

    >
    > > Yes.

    >
    > > > (bad cabeling),

    >
    > > Or something else turned the DMA off.

    >
    > > > may be excessive fragmentation.

    >
    > > Nope, you wont get that dramatic a result from that.


    > Oh, yes. You can get even worse. I have seen it.


    That's what a cooked brain does for you, babblebot.

    > Remember that this is an average over 77GB.


    Exactly. Which is exactly why that value is so *dramatic*, babblebot.
    It means that the low(est) values in the range that make up for
    that average must be even *dramatically* low(er than 6MB/s).
    With 1MB/s being the bottom for that, that means a very high
    (ie *dramatic*) degree of fragmentation.

    >
    > > > May also be bad sectors or other disk issues.

    >
    > > Yep. And the best way to check for that is the SMART report,
    > > after breaking the RAID array if necessary to do that.


    > Actually the way to do this is to attach the disks to a different controller


    Nope, if breaking the array is yielding the same result.

    > and never acess them in R/W mode.


    Which isn't necessarily a problem.

    > E.g. Knoppix can help here.
    >
    > Arno


  18. Re: Very slow copying data from RAID 1 array.

    231 wrote in news:4753c7fe$0$22921$5a62ac22@per-qv1-newsreader-01.iinet.net.au
    > Arno Wagner wrote:
    > > Previously 231 <231@alok.com> wrote:
    > > > Arno Wagner wrote:
    > > > > Previously 231 <231@alok.com> wrote:
    > > > > > Arno Wagner wrote:
    > > > > > > Previously Ian R wrote:
    > > > > > > > Hi
    > > > > > >
    > > > > > > > I have a 500GB RAID1 array using brand new Western Digital drives
    > > > > > > > and the Sil 3114 chipset on my ASUS A8N-SLI Premium system board.
    > > > > > >
    > > > > > > > I use the RAID to store partition backup image files which are
    > > > > > > > split into multiple 2GB segments. The backup segments total
    > > > > > > > approx 70Gb.
    > > > > > >
    > > > > > > > Each week I copy the image files to a removable hard drive which
    > > > > > > > usually takes approx 25-30mins.
    > > > > > >
    > > > > > > > However today after selecting all the segments (77GB Total) and
    > > > > > > > beginning the copy,
    > > > > > > > Windows is estimating over 200 minutes for the copying!
    > > > > > >
    > > > > > > > I had similar trouble a few months ago so ran a disc check on the
    > > > > > > > RAID array which took over 30hrs to complete! It seemed to fix
    > > > > > > > whatever errors it found as since then it ran normally taking
    > > > > > > > approx 25-30mins to copy the files.
    > > > > > >
    > > > > > > > However today the same lengthy copying problem has recurred.
    > > > > > >
    > > > > > > > Any idea what might cause this?
    > > > > > >
    > > > > > > > Right now I'm thinking I'll need to reformat the drives but I'll
    > > > > > > > have to buy another 500GB drive to painstakingly copy all the
    > > > > > > > data off the RAID array first! Bummer!
    > > > >
    > > > > > > 30 min for 77GB is about 42MB/s. That is pretty good. 200 min
    > > > > > > is about 6MB/s. Quite slow. May be PIO instead of DMA on a disk
    > > > >
    > > > > > Yes.
    > > > >
    > > > > > > (bad cabeling),
    > > > >
    > > > > > Or something else turned the DMA off.
    > > > >
    > > > > > > may be excessive fragmentation.
    > > > >
    > > > > > Nope, you wont get that dramatic a result from that.

    > >
    > > > > Oh, yes.

    > >
    > > > Nope.

    > >
    > > > > You can get even worse.

    > >
    > > > Nope.

    > >
    > > > > I have seen it.

    > >
    > > > No you havent.

    > >
    > > > > Remember that this is an average over 77GB.

    > >
    > > > You cant get a 7/1 reduction in thruput due to excessive
    > > > fragmentation.

    > >
    > > > The size is irrelevant to that.

    >
    > > You have no clue what you are talking about, obviously.

    >
    > We'll see...
    >
    > > The worst case, and it can be reached in practice, is one seek per cluster.

    >
    > That never ever happens in practice.


    > > If we assume 16kB clusters and a 7200rpm disk with 10ms seek
    > > time and 4ms average latency, that comes down to just over 1MB/s.


    16 kB / 80 MB/s = .2 ms per cluster transfer time (!)
    1 cluster per 14.4 ms = 70 clusters per second = 1.11 MB/s average

    Or from a dutycycle perspective:
    ..2 / (10 + 4.2 + .2) * 80 MB/s = 1.11 MB/s average

    (!) 80MB/s STR for convenience, but not unrealistic.

    >
    > Nope.


    Nope, Roddles?

    >
    > > That is without any accesses for the management
    > > information and time to actually read anything.

    >
    > Wrong, as always.


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