what kind of read/write speeds should I expect with RAID10

  • I'm new to OMV and RAID in general. This is really my first setup. I setup OMV as a VM in ESXi. I connected four 8TB WD80EFZX 5400RPM HDDs in RAID10. What kind of read/write speed should I expect to be getting? I tried NAS performance tester 1.7 and I got an average write speed of 67 MB/sec and average read speed of 95 MB/sec. This seems a bit slow to me, but I don't really have anything to compare it to other than copying directly to a HDD. Help is appreciated.

  • normal use of 1 HDD.

    So you're saying if I had 100 MB/sec write speeds on a local HDD, I should get 200 MB/sec write speeds in the RAID? That's not the case as you can see above. What kind of diagnostics can I do to investigate this?


    Also, when I was looking around the OMV UI, I noticed that in the RAID Management page, my raid is showing up with a "clean, degraded" state. What does that mean? I just set up this raid 2 weeks ago with brand new HDDs. What does degraded mean? I checked the smart values of the drives and they're all green/good.


    Here are some outputs:


    cat /proc/mdstat


    Code
    Personalities : [raid10] [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4]
    md0 : active raid10 sde[3] sdc[1]
    15627790336 blocks super 1.2 512K chunks 2 near-copies [4/2] [_U_U]
    bitmap: 117/117 pages [468KB], 65536KB chunk
    unused devices: <none>

    Anything else I can provide?

  • theoricaly yes. But hardware, bios, controllers, motherboard are a factor in that theorize.


    http://www.raid-calculator.com/default.aspx


    http://www.hardwaresecrets.com…aid0-really-increase-disk



    When you create an array, it gets mostly 2 status:
    - clean: everything is working fine. Hardware is good, data status is good.
    - degraded: something wrong, or creation synchronization of data is not finish.


    An raid 6 array of 6 HDD of 1TO takes up to three hours to initialize and depending of system will appears as building, degraded or synchronizing...

  • Re,

    4x read and 2x write speed gain

    absolutely theoretically ...


    When you create an array, it gets mostly 2 status:

    or broken/dead/false ...


    What does degraded mean?

    That one or more drives are missing. In your mdstat-output are only two of four drives listed and stated ...


    You should fix that first - look in the logs for information about the failing drives!


    Sc0rp

  • Thank you for pointing again the most obvious theorical statement i wrote:


    "theoricaly yes. But hardware, bios, controllers, motherboard are a factor in that theorize."
    "When you create an array, it gets mostly 2 status:" forget to add death because it did not mention it, broken because some system dont even mention it and go directly for degraded.
    "degraded: something wrong, or creation synchronization of data is not finish." means a disk is missing, or data is corrupted, or sync is not finis, or alien are really from mars !!! HO NO, i did forget to mention a disk might be missing.


    And concerning degraded array, the most simple but not obvious cause is a BAD SATA CABLE: clean, degraded array state after only a couple weeks of setting it up

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