2008 mac pro raid0 questions

Discussion in 'Mac Pro' started by sbab, May 28, 2013.

  1. sbab macrumors member

    Oct 25, 2012
    This is my first attempt at raid.
    The raid disk will be the data disk, I will be using an SSD for the boot drive.
    I have installed 2x2tb seagate hd's in my 2008 macpro and made a 4tb raid0 drive using the software raid in disk utility.
    At this stage the data disk is empty and just for testing as I'm trying to setup the raid for best performance, i.e. adjust block size.
    It all seems to go ok and what I want to do is test it properly to verify its operation.
    I have a sata3 card fitted to the backplane so all the hd's can use 6g. I hope...
    Initially my tests looked OK in the higher range but I noticed what I thought was a poor result in most of the random read/writes, with what I've seen they looked low. Maybe I haven't done something right with the testing apps!
    I have AJA, Black Magic and Quickbench. I like Quickbench because it gives so much more info about the disks.
    I would like to know what settings on any of these testers you would use, cache on/off etc, to obtain accurate readings.
    I have used different block sizes in my tests and I didn't see much of a result between them.
    Just how important are the random read/writes on a data disk?
    I've only spent a short time getting acquainted with raid so very much the noob.
    Results to follow after suitable testing.
  2. TheEasterBunny macrumors 6502

    Jan 22, 2013
  3. sbab thread starter macrumors member

    Oct 25, 2012
    I used striped.
    This will take up some room so I'll just post the results and wait maybe for a reply, thanks.

    The following are the test results, the first using raid and 32k blocks.

    1. Standard Test Results: Raid0 32k block size
    Test Cycles: 5

    Transfer Size Sequential Read Sequential Write Random Read Random Write

    4 KBytes 32.207 MB/Sec 28.875 MB/Sec 0.689 MB/Sec 1.493 MB/Sec
    8 KBytes 56.046 MB/Sec 54.150 MB/Sec 1.562 MB/Sec 3.143 MB/Sec
    16 KBytes 101.315 MB/Sec 87.391 MB/Sec 2.908 MB/Sec 5.133 MB/Sec
    32 KBytes 161.530 MB/Sec 168.464 MB/Sec 6.592 MB/Sec 8.281 MB/Sec
    64 KBytes 265.985 MB/Sec 285.315 MB/Sec 12.810 MB/Sec 16.571 MB/Sec
    128 KBytes 421.327 MB/Sec 397.622 MB/Sec 24.201 MB/Sec 36.025 MB/Sec
    256 KBytes 549.642 MB/Sec 486.039 MB/Sec 43.871 MB/Sec 63.315 MB/Sec
    512 KBytes 648.303 MB/Sec 538.372 MB/Sec 72.402 MB/Sec 104.615 MB/Sec
    1024 KBytes 692.407 MB/Sec 594.250 MB/Sec 100.022 MB/Sec 141.703 MB/Sec

    Standard Ave 325.418 MB/Sec 293.386 MB/Sec 29.451 MB/Sec 42.253 MB/Sec

    Large Test Results:

    Transfer Size Large Read Large Write

    2 MBytes 803.635 MB/Sec 616.384 MB/Sec
    3 MBytes 685.136 MB/Sec 626.570 MB/Sec
    4 MBytes 845.877 MB/Sec 630.595 MB/Sec
    5 MBytes 645.091 MB/Sec 635.469 MB/Sec
    6 MBytes 466.784 MB/Sec 639.482 MB/Sec
    7 MBytes 501.296 MB/Sec 638.560 MB/Sec
    8 MBytes 456.752 MB/Sec 640.056 MB/Sec
    9 MBytes 465.750 MB/Sec 640.605 MB/Sec
    10 MBytes 466.139 MB/Sec 643.089 MB/Sec

    Large Ave 592.940 MB/Sec 634.534 MB/Sec

    Here are the Non raid test results

    2. Standard Test Results: NON raid - 2 disks tested, both results about same
    Test Cycles: 5

    Transfer Size Sequential Read Sequential Write Random Read Random Write

    4 KBytes 38.194 MB/Sec 30.607 MB/Sec 0.726 MB/Sec 0.918 MB/Sec
    8 KBytes 66.639 MB/Sec 61.200 MB/Sec 1.588 MB/Sec 1.712 MB/Sec
    16 KBytes 118.177 MB/Sec 106.902 MB/Sec 3.123 MB/Sec 3.201 MB/Sec
    32 KBytes 190.635 MB/Sec 163.613 MB/Sec 6.401 MB/Sec 6.236 MB/Sec
    64 KBytes 271.088 MB/Sec 222.212 MB/Sec 13.881 MB/Sec 11.952 MB/Sec
    128 KBytes 351.630 MB/Sec 242.460 MB/Sec 23.455 MB/Sec 26.447 MB/Sec
    256 KBytes 404.650 MB/Sec 299.706 MB/Sec 44.138 MB/Sec 48.089 MB/Sec
    512 KBytes 436.732 MB/Sec 318.773 MB/Sec 62.349 MB/Sec 64.660 MB/Sec
    1024 KBytes 459.411 MB/Sec 331.974 MB/Sec 79.137 MB/Sec 91.295 MB/Sec

    Standard Ave 259.684 MB/Sec 197.494 MB/Sec 26.089 MB/Sec 28.279 MB/Sec

    Large Test Results:

    Transfer Size Large Read Large Write

    2 MBytes 470.938 MB/Sec 342.040 MB/Sec
    3 MBytes 324.863 MB/Sec 344.302 MB/Sec
    4 MBytes 266.344 MB/Sec 346.380 MB/Sec
    5 MBytes 246.385 MB/Sec 347.358 MB/Sec
    6 MBytes 239.709 MB/Sec 347.847 MB/Sec
    7 MBytes 230.990 MB/Sec 329.735 MB/Sec
    8 MBytes 212.240 MB/Sec 281.921 MB/Sec
    9 MBytes 199.427 MB/Sec 252.457 MB/Sec
    10 MBytes 198.614 MB/Sec 282.871 MB/Sec

    Large Ave 265.501 MB/Sec 319.435 MB/Sec
  4. TheEasterBunny macrumors 6502

    Jan 22, 2013
    Looks about right at 1.8 to 1.9 times the single drive speeds.
    What will you be doing with your Pro?
    The answer to that question tells you what block sizes will work the best for you.
  5. sbab thread starter macrumors member

    Oct 25, 2012
    What do I want to do? Initially it was just to get rid of the spinning beachball. Now I want a mac that runs fast in a practical sense that takes full advantage of my setup.

    After visiting a few forums and reading what others have done made me feel like, wow I want one of those, ooh I like that.

    Anyway back to basics.
    I have a 120G SSD os/apps boot drive with about 70G used.
    A 2tb data drive with 240G user directory and 500G of itunes yet to be added.

    I am now trying to make a data drive with a raid0 array comprising 2x2tb drives and was trying to select a block size to take advantage of my usage, for which I'm asking for help.

    I don't use my mac in any business.
    I don't edit movies, move large files and I don't play games.
    My usage is general in nature. email, internet etc. I use databases and spreadsheets but no way near any business level. I have photoshop and have edited/restored many old 35mm slides.

    4Ttb storage for 750G sounds like overkill but I would like to continue with it, even if it's only for the exercise.

    A 500G SSD with os/apps/user directory and the itunes on a fast HD is perhaps another option.

    So, I would like to complete the raid setup with your help and listen to any further suggestions to do it better.

    Another point you might explain, from what I've seen the random read/writes of a SSD are in general higher than those of a HD.
    Does this make them good for small transfer work?
    I have most probably got this wrong or haven't taken something into account. I'm interested to know. Maybe Raid SSD???
  6. TheEasterBunny macrumors 6502

    Jan 22, 2013
    I'm sure others will point out if I'm incorrect, but since you will primarily be using smaller file transfers, a 32k block should work out just fine.
    The SSD as the boot drive with OS and apps is ideal.
    Personally I use a RAID0 with 2 SSD's for my boot drive, and apps.
    I have not used RAID for my data drives yet, but that will be next.
    I do some larger file stuff like encoding video, so I selected larger blocks.

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