Posts by m0nKeY

    Hi everyone,

    I'm new here and just started to work with OMV because I build me a NAS/VM Server for private usage. I'm an embedded software developer from Germany, so I'm able to understand most technical things, however I'm not a Linux-expert. :-) I just wanted to give you some background and sorry for my bad English.

    Ok, so let's start to describe my problem. I brought me a DELL T20 and put the hardware into a new case, brought 8 WD Red with 3TB, a SATA Controller, a SSD and some additional RAM and put everything together. Because I wanted to use the T20 for other services then a file server, too and because just out of curiosity, I installed XenServer 7 on it. Then I installed OMV3 into a VM and passed the SATA controller though to the VM. At first everything seemed to be ok, but after I enabled the HDD Write Cache in OMV, the Kernel started to throw ATA Error messages while coping files onto the server:


    At first I thought one of my disk were defect, so I permord a extended SMART test on every disk:

    smartctl -a /dev/sda:


    As far as I can tell, the SMART data seems ok. So I started to switch the SATA cabels to other HDDs, traced back the ATA Channel to the actual device and noted the Serial-Number to determine if one special HDD is causing the problem, but I could not see any similarities between them. I got this errors with 6 HDDs. So for me, and I'm hoping that i'm right, not a HDD is causing the problem. I suspect it is the SATA controller or the fact, that I use PCI-Passthrough.

    Anyway the write performance seems to be pretty bad, too:

    dd if=/dev/zero of=testfile bs=1G count=1 (with cache enabled):

    dd if=/dev/zero of=testfile bs=1G count=1 (without cache enabled):

    Here some information about the raid:

    mdadm --examine --brief --scan --config=partitions:

    mdadm --detail /dev/md127:

    I assigned 2 V-Cores to the VM and 6GB RAM. I also disabled the idle3-timeout on the WD Red HDDs. Any ideas what could cause this problem? Can you help me? ;( I'm using OMV 3.0.64.