I had a previous thread where I thought the crashes were being caused by a new RAID controller. After troubleshooting and resolving a few unrelated matter I am back to discuss the current setup.

 

Latest UnRaid running on a i7 980Extreme. with 12GB of ram.

6GB and 4 cores pinned to the VM

 

Unraid is running a few dockers and 7 disks.

Plex

CouchPotatos

Sonar

Dropbox

SabNZBD

 

 

So what I have figured out when a large download is processing  in SAB the memory usage in UnRaid spike up to 6 - 7GB. As soon as this happens the VM dies.

 

To alleviate for now I have dropped the Windows VM down to 4GB and seems mostly ok. Some of the tasks I am running in the VM are suffering though (mainly using for BlueIris DVR).

 

It seems UnRaid is over-running the memory space of the VM and when this happens the VM dies. I am surprised this can happen and would not be prevented.

 

Thoughts answers or questions?

 

Many thanks,

 

Mike

when this happens, what is the memory usage of unraid?  If unraid is running out of memory, I would think it is doing the right thing shutting down the vm so as not to crash the host/unraid.

You are correct. 12GB total ram - 6GB for VM, 6GB remaining.

When I actually witnessed, UnRaid was showing 6.5-7GB usage.

 

What happens in a low memory machine running UnRaid only. For example if I had 4GB ram and was running the dockers mentioned above. Does UnRaid not do any swapping of any sort? Does it just crash if it runs out of memory?

I think its a different situation when all the physical memory is used up as opposed to it being loaned to a VM.

 

however, this is over my head at that point so maybe one of the SMEs could better answer that part.

Thanks for the replies..

 

I am out of my league as well.. Part of why I am asking. I was under the impression that the memory like the CPU would pinned to the VM and not available to the Host.

I would rather the VM die then UnRaid crash but it seems strange that they would not have other mechanisms in place in unraid to provide for high memory usage.

 

In the ideal world I would just add a pile of memory to the server but I have been having some slot issues that make me nervous to put any money into this board. With the Canadian Dollar as it is, upgrading CPU and/or Board is just not an option I don't think.

 

 

I think its a different situation when all the physical memory is used up as opposed to it being loaned to a VM.

 

however, this is over my head at that point so maybe one of the SMEs could better answer that part.

reviving this older post so I dont start a new one!

 

My Linux VM (18.04) crashes with high RAM usage. UNRAID has 128GB and VM take 100G (min/max same) and 28vCPUs (a lot more to spare). Last 'htop' ssh screen I had before crashing was with ~80GB usage from multithreaded python code that I;ve used it many many times.

 

Any data analysis/ML people here that use the unraid VMs to the max?

 

Thanks 

I am a long way from pro... It maybe worth starting a new thread to gain some more eyes.. I would also look at posting logs to help out those in the know... 

 

For me I did end up replacing the Motherboard/CPU and adding ram.. I had some extra hardware I was able to swap around... Sounds like you already have killer hardware so guessing that is not an option :-)

 

Good luck!

11 hours ago, daemonix said:

UNRAID has 128GB and VM take 100G

Keep in mind KVM uses resources to manage the VM's resources, so you may be simply running out of RAM. Unraid as it ships doesn't configure any swap space, so processes that would normally get swapped out are stuck in physical RAM, and some caching and performance tuning is configured as a percentage of total RAM as well, which increases the RAM allocated by unraid. Try reducing your VM RAM allocation and see if the behaviour changes.

7 hours ago, jonathanm said:

Keep in mind KVM uses resources to manage the VM's resources, so you may be simply running out of RAM. Unraid as it ships doesn't configure any swap space, so processes that would normally get swapped out are stuck in physical RAM, and some caching and performance tuning is configured as a percentage of total RAM as well, which increases the RAM allocated by unraid. Try reducing your VM RAM allocation and see if the behaviour changes.

 

I will try but as I monitor both unraid and VM with htop all the time, unraid never moved above the 100+(4or5)Gb or total usage.

Ill try doing the same test on a 256GB system.

18 hours ago, bedpan said:

I am a long way from pro... It maybe worth starting a new thread to gain some more eyes.. I would also look at posting logs to help out those in the know... 

 

For me I did end up replacing the Motherboard/CPU and adding ram.. I had some extra hardware I was able to swap around... Sounds like you already have killer hardware so guessing that is not an option ?

 

Good luck!

Thanks,

Yes the boxes I have are all 'top' spec and I had them running the same codes before unraid (bare ubuntu). Ill re-test and see.