2 of 10 hard drives very slow

  • My omv setup has 8 Hard Drives (7200 and 5400) with good transfer rates (+90 to +100 MB/s WRITE). (tested with HELIOS LAN Test)
    FYI: All of those Hard Drives where external 3.5" HDD in an enclosure.
    I dislocated those Hard Drives and put them into an 8 bay enclosure.


    However 2 Hard Drives, when put into the same enclosure, have poor transfer rates (10 MB/s).
    (Those drives have also been external ones that I extracted from their case.)
    I switched their places in the enclosure many times to make sure that its the disks and not the SATA connectors of the enclosure that cause the low transfer rate.
    With those 2 drives HELIOS LAN test did't give me any readings but a spinning wheel.
    The 10 MB/s where displayed during the copying of files (via SAMBA share).


    I've copied OMV's SMART extended info from the 2 slow drives and from one of the fast drives (full info is in the attached txt files):


    slow drive 1:


    slow drive 2:

    fast drive:


  • I dislocated those Hard Drives and put them into an 8 bay enclosure

    How is the connection done? USB or eSATA?


    I would use LanTest only for combined storage/network tests and use iozone for a test of storage performance only.


    Code
    cd /srv/$your-disk
    iozone -e -I -a -s 500M -r 1024k -r 16384k -i 0 -i 1

    Running iozone might require installing the iozone3 package first.


    BTW: SMART values look ok, only one disk has a few CRC errors you should have a look at (indication of cable/connector problems and shouldn't further increase).

  • connection is USB 3.


    iozone with a good disk:


    iozone with slow drive 1 (S/N WF3055FH):
    (that test took way more time than the first one with the good disk.)

  • that test took way more time than the first one with the good disk

    Sure, with the good disk you got 130 MB/s in both directions while the slow one only achieves 6.5 MB/s write and ~30 MB/s read. But no idea what could cause this. Do you have the chance to test with the two slow disks connected directly to a real SATA controller?

  • The second disk shows even slower WRITE

    Code
    kB  reclen    write  rewrite    read    reread    read     write     read   rewrite      read   fwrite frewrite    fread  freread
              512000    1024     4681     4653   151900   151306                                                                          
              512000   16384     4676     4686   148618   148507

    I have the Nanopi's SATA HAT
    but I have no external power supply at the moment.
    I might find some lying around somewhere.

  • the slow drive connected via SATA:

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