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  • How To Benchmark Disk I/O
    08/14/2014 12:24PM

    Here is a quick snipped on how to benchmark Disk I/O with dd.

    $ time sh -c "dd if=/dev/zero of=/home/rchapin/test.zeros bs=1024k count=10000 && sync"

    10000+0 records in
    10000+0 records out
    10485760000 bytes (10 GB) copied, 81.4124 s, 129 MB/s

    real    1m21.950s
    user    0m0.810s
    sys     0m5.474s


    Will do a write test of 10GB.

    You can do a similar test and read from that file generated and write to another file or /dev/null to get an idea of the read speeds.

    See the this link for more information.

  • Clone and Backup a Bootable USB Drive
    03/09/2014 10:19AM

    We recently got a new ASUS laptop for the boys to use (I'll use it too, it's pretty sweet) which came with Windows 8.

    It did not come with the install CD or license key, but included a recovery partition and the key in the BIOS.  Now that we've had it for a few weeks and verified that all of the hardware works, we are going to put Ubuntu on it, but I wanted to make sure that I would still be able to use the Windows 8 license on it if I wanted.

    So, using the Win8 recovery program, I createad a bootable recovery disk onto a USB stick and I wanted to back it up, as well as be able to make a clone of it if need be.

    Following are the dd commands to make that happen:

    First, do a tail of /var/log/messages before you plug in the usb drive.  You should see it be recognized by the machine as sd[something].  Or, you can do an fdisk -l and should see the usb stick (as well as the other drives on your machine)

    Be warned, make sure that you have the devices correct before you run these commands or you may destroy data on your machine.

    Assuming that the usb stick is sdg, clone the disk to a file on another computer

    dd if=/dev/sdg of=./windows_8_rcvry_usb_asus.dd conv=notrunc

    Copy the file to another USB stick (assuming that /dev/sdg is the USB drive because all data on /dev/sdg will be destroyed during this operation):

    dd if=./windows_8_rcvry_usb_asus.dd of=/dev/sdg conv=notrunc

    Just make sure that the usb drive to which you are copying is the same size or larger than the original one that you copied from.

  • Problems with WD Caviar Green SATA Drives
    11/06/2009 1:28PM

    I needed a couple of 1 TB SATA drives to put into external enclosures.

    I have found that in many cases MicroCenter offers prices very close to that found on Amazon, and/or Buy.com.? The thing that I really like about MicroCenter is that they actually have knowledgeable sales people.? When seeing if the drives that I was looking for were in stock the sales associated told me that I wanted to stay away from any of the "Green" drives.? In his experience, not only were they considerably slower (which in this case, didn't make much of a difference to me) but that their reliability was very poor.? The "Green" drives spin at variable speeds so that they will consume less energy.? Evidently, the variable speed mechanism hasn't been sorted out completely and results in catastrophic hardware failure.

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