Tracking down IOwait cause

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I need some help... I have been having high IOwaits for a few months now. Its driving me up the wall...



Unraid system: Unraid server Pro, version 6.8.3

Model: Custom

Motherboard: Supermicro - X8DT6

Processor:Intel® Xeon® CPU E5620 @ 2.40GHz

HVM: Enabled

IOMMU: Disabled

Cache:L1-Cache = 256 kB (max. capacity 256 kB)

L2-Cache = 1024 kB (max. capacity 1024 kB)

L3-Cache = 12288 kB (max. capacity 12288 kB)

Memory: 48 GB (max. installable capacity 384 GB)

Network:bond0: fault-tolerance (active-backup), mtu 1500

eth0: 1000Mb/s, full duplex, mtu 1500

Kernel:Linux 4.19.107-Unraid x86_64


P + Q algorithm:5892 MB/s + 8187 MB/s


Steps to fix issues:

I have been having a high amount of IOwait issues. I have tried everything that has been the issue for others:

  • Add a second SSD to cache
  • Move Deluge to its own SSD via unmounted drives
  • Switched from Plex to Emby
  • Added a nVidia 1660 Ti for Emby
  • Disabled and removed Dynamix Cache Directories, waited a week and re-added it
  • DiskSpeed docker on all drives
  • Changed the Parity drive to Seagate Ironwolf Pro (second one still in shipping put in a HP Enterprise as temp Parity)
  • Replaced all drives what errors (even ones with 1 error 3 drives)
  • Disabled the specter and meltdown protections
  • Replaced both CPU Coolers with dual noctua fans
  • Added Memory fans to the system, to solve memory heat issues
  • Change to a new case (Fractal design define 7lx) from 24 bay supermicro
    • Added 8 case fans
    • Using 18 - 3.5 drives and 5 - 2.5 drives
  • Removed all 1 TB drives
  • Watched NetData, htop and Glances like a hawk for any signs as to what it causing the issue


I am still getting the IOwait errors messages, and the system is very slow.

Screen Shot 2020-05-02 at 8.27.14 PM.png

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  • 10 months later...

@Exilepc - Did you ever find a fix for this? I am getting the same issues, and while copying large amounts of data to the array it kills the WebUI's for the server itself, and all the docker containers. 

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