I rebuilt the VM w/ Ubuntu 14 which is what the raid was built on and ran fine for years. I had one freeze the next day, but after a re-sync it has been stable for about a week. I suspect its a mix between my VMKernel and Ubuntu 16 Problem, but I doubt I'll ever know. My suggestion if you get this error, change your Kernel/OS version

Update: a few weeks later one of the cores on my CPU died. If you see this error you may want to consider that your CPU is overheating or malfunctioning.

TLDR; About a Week Later I lost a CPU Core likely due to overheating/badly placed heatsink/fan.

• If you are using ESXi I would fire up another OS and check on Temp's and/or consider re-seating your CPU heat sink.

• This post has got a lot of views, and when I had the issue, google had very little information for me. Please share your experiences in comments or answers!

TimeLine:

• I get error about Jiffies
• Have to use power button to reboot
• MDADM Array Rebuild --> Successful.
• I get another error next day
• Reboot/Rebuild Successful.
• Another error!
• Rebuild VM w/ new OS
• Stable for about a week
• Single Core in CPU dies!

Further research into ESXi showed me that ESXi does NOT gather device Temps without some sort of advanced hardware addition that I didn't have (Possibly because I wasn't use a computer from the "Hardware Compatibility List". (https://communities.vmware.com/thread/547244). If it had, ESXi could have likely throttled my CPU. I now use KVM which checks all my device Temps via normal methods and reacts accordingly. Not just that but my RW speed has greatly increased as my Hypervisor is now also my FileServer vs before I had to passthrough the disks to a FileServer VM since ESXi doesn't support SMB/NFS/MDADM etc. (I'm talking about a 2 or 3 fold increase in RW speeds now that my clients talk directly to the Hypervisor/FileServer).

I rebuilt the VM w/ Ubuntu 14 which is what the raid was built on and ran fine for years. I had one freeze the next day, but after a re-sync it has been stable for about a week. I suspect its a mix between my VMKernel and Ubuntu 16 Problem, but I doubt I'll ever know. My suggestion if you get this error, change your Kernel/OS version.

I rebuilt the VM w/ Ubuntu 14 which is what the raid was built on and ran fine for years. I had one freeze the next day, but after a re-sync it has been stable for about a week. I suspect its a mix between my VMKernel and Ubuntu 16 Problem, but I doubt I'll ever know. My suggestion if you get this error, change your Kernel/OS version

Update: a few weeks later one of the cores on my CPU died. If you see this error you may want to consider that your CPU is overheating or malfunctioning.