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NSLU2 w/Debian - USB Speed

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  • tleegaard
    Hi there, I ve problems with the speed rate on the NSLU2. I have attached both an usb-stick and an external HDD to the USB-ports. Transfer rates for the
    Message 1 of 5 , Sep 9, 2010
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      Hi there,

      I've problems with the speed rate on the NSLU2. I have attached both an usb-stick and an external HDD to the USB-ports.

      Transfer rates for the usb-stick are ok but as you can see below transfer rates for the HDD is really slow.

      USB-STICK
      NSLU:~# dd if=/dev/sda1 of=/dev/null bs=1000 count=10000
      10000+0 records in
      10000+0 records out
      10000000 bytes (10 MB) copied, 1.15959 s, 8.6 MB/s

      EXTERNAL HDD
      NSLU:~# dd if=/dev/sdb1 of=/dev/null bs=1000 count=1000
      1000+0 records in
      1000+0 records out
      1000000 bytes (1.0 MB) copied, 2.05157 s, 487 kB/s

      Can anyone suggest a solution to the problem?
    • Carl Lowenstein
      ... Make the block size (bs) a multiple of the physical sector size of the disk. (multiple of 512) Otherwise, you are probably reading one (1000-byte) block
      Message 2 of 5 , Sep 9, 2010
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        On Thu, Sep 9, 2010 at 12:36 AM, tleegaard <tleegaard@...> wrote:
        >
        >
        >
        > Hi there,
        >
        > I've problems with the speed rate on the NSLU2. I have attached both an usb-stick and an external HDD to the USB-ports.
        >
        > Transfer rates for the usb-stick are ok but as you can see below transfer rates for the HDD is really slow.
        >
        > USB-STICK
        > NSLU:~# dd if=/dev/sda1 of=/dev/null bs=1000 count=10000
        > 10000+0 records in
        > 10000+0 records out
        > 10000000 bytes (10 MB) copied, 1.15959 s, 8.6 MB/s
        >
        > EXTERNAL HDD
        > NSLU:~# dd if=/dev/sdb1 of=/dev/null bs=1000 count=1000
        > 1000+0 records in
        > 1000+0 records out
        > 1000000 bytes (1.0 MB) copied, 2.05157 s, 487 kB/s
        >
        > Can anyone suggest a solution to the problem?

        Make the block size (bs) a multiple of the physical sector size of
        the disk. (multiple of 512)
        Otherwise, you are probably reading one (1000-byte) block per
        revolution, made up of parts of two or three adjacent sectors.

        carl
        --
        carl lowenstein  <clowenstein@...>
      • DaylanDarby
        You also might want to up your count (1.0 MB of copy stats probably is big enough to make a valid test)
        Message 3 of 5 , Sep 9, 2010
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          You also might want to up your count (1.0 MB of copy stats probably is
          big enough to make a valid test)

          On 09/09/2010 10:16 AM, Carl Lowenstein wrote:
          > On Thu, Sep 9, 2010 at 12:36 AM, tleegaard<tleegaard@...> wrote:
          >
          >>
          >>
          >> Hi there,
          >>
          >> I've problems with the speed rate on the NSLU2. I have attached both an usb-stick and an external HDD to the USB-ports.
          >>
          >> Transfer rates for the usb-stick are ok but as you can see below transfer rates for the HDD is really slow.
          >>
          >> USB-STICK
          >> NSLU:~# dd if=/dev/sda1 of=/dev/null bs=1000 count=10000
          >> 10000+0 records in
          >> 10000+0 records out
          >> 10000000 bytes (10 MB) copied, 1.15959 s, 8.6 MB/s
          >>
          >> EXTERNAL HDD
          >> NSLU:~# dd if=/dev/sdb1 of=/dev/null bs=1000 count=1000
          >> 1000+0 records in
          >> 1000+0 records out
          >> 1000000 bytes (1.0 MB) copied, 2.05157 s, 487 kB/s
          >>
          >> Can anyone suggest a solution to the problem?
          >>
          > Make the block size (bs) a multiple of the physical sector size of
          > the disk. (multiple of 512)
          > Otherwise, you are probably reading one (1000-byte) block per
          > revolution, made up of parts of two or three adjacent sectors.
          >
          > carl
          > --
          > carl lowenstein<clowenstein@...>
          >
          >
        • tleegaard
          ... NSLU:~# dd if=/dev/sdb1 of=/dev/null bs=1024 count=1000 1000+0 records in 1000+0 records out 1024000 bytes (1.0 MB) copied, 1.70798 s, 600 kB/s I suppose
          Message 4 of 5 , Sep 10, 2010
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            --- In nslu2-general@yahoogroups.com, Carl Lowenstein <clowenstein@...> wrote:
            >
            > On Thu, Sep 9, 2010 at 12:36 AM, tleegaard <tleegaard@...> wrote:
            > >
            > >
            > >
            > > Hi there,
            > >
            > > I've problems with the speed rate on the NSLU2. I have attached both an usb-stick and an external HDD to the USB-ports.
            > >
            > > Transfer rates for the usb-stick are ok but as you can see below transfer rates for the HDD is really slow.
            > >
            > > USB-STICK
            > > NSLU:~# dd if=/dev/sda1 of=/dev/null bs=1000 count=10000
            > > 10000+0 records in
            > > 10000+0 records out
            > > 10000000 bytes (10 MB) copied, 1.15959 s, 8.6 MB/s
            > >
            > > EXTERNAL HDD
            > > NSLU:~# dd if=/dev/sdb1 of=/dev/null bs=1000 count=1000
            > > 1000+0 records in
            > > 1000+0 records out
            > > 1000000 bytes (1.0 MB) copied, 2.05157 s, 487 kB/s
            > >
            > > Can anyone suggest a solution to the problem?
            >
            > Make the block size (bs) a multiple of the physical sector size of
            > the disk. (multiple of 512)
            > Otherwise, you are probably reading one (1000-byte) block per
            > revolution, made up of parts of two or three adjacent sectors.
            >
            > carl
            > --
            > carl lowenstein  <clowenstein@...>
            >

            NSLU:~# dd if=/dev/sdb1 of=/dev/null bs=1024 count=1000
            1000+0 records in
            1000+0 records out
            1024000 bytes (1.0 MB) copied, 1.70798 s, 600 kB/s

            I suppose this is what you mean? But I can't see the big difference..
            When transfering to the HDD with SSH/FTP the transfer speed is only about 600-800 kB/s aswell..
          • Bob George
            ... I seem to be getting better performance with a nothing-special Western Digital 40GB external USB drive: # lsb_release -d Description: Debian GNU/Linux
            Message 5 of 5 , Oct 2, 2010
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              On Fri, Sep 10, 2010 at 11:58 AM, tleegaard <tleegaard@...> wrote:

              >
              > [...]
              > NSLU:~# dd if=/dev/sdb1 of=/dev/null bs=1024 count=1000
              > 1000+0 records in
              > 1000+0 records out
              > 1024000 bytes (1.0 MB) copied, 1.70798 s, 600 kB/s
              >
              > I suppose this is what you mean? But I can't see the big difference..
              > When transfering to the HDD with SSH/FTP the transfer speed is only about
              > 600-800 kB/s aswell..
              >

              I seem to be getting better performance with a nothing-special Western
              Digital 40GB external USB drive:

              # lsb_release -d
              Description: Debian GNU/Linux 5.0.6 (lenny)

              # cat /proc/cpuinfo
              Processor : XScale-IXP42x Family rev 1 (v5l)
              BogoMIPS : 266.24

              # dd if=/dev/sda1 of=/dev/null bs=1024 count=1000
              1000+0 records in
              1000+0 records out
              1024000 bytes (1.0 MB) copied, 0.712626 s, 1.4 MB/s

              # hdparm -t /dev/sda

              /dev/sda:
              Timing buffered disk reads: 36 MB in 3.08 seconds = 11.69 MB/sec

              - Bob


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