I got this last night.

I suspect the macOS VM (which I usually don't run) pushed me over the edge.

 

Diagnostics attached.

If you spot anything out of the ordinary I'd appreciate the assistance.

nas-diagnostics-20230206-0732.zip

I got another out of memory error warning (killed a VM):

Mar  6 02:48:28 NAS kernel: oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/machine/qemu-4-macOS.libvirt-qemu,task=qemu-system-x86,pid=15774,uid=0
Mar  6 02:48:28 NAS kernel: Out of memory: Killed process 15774 (qemu-system-x86) total-vm:4771316kB, anon-rss:4437356kB, file-rss:0kB, shmem-rss:26488kB, UID:0 pgtables:9400kB oom_score_adj:0

 

Seems like I just ran out of memory.

But reporting (just prior to the error) showed 9GB used and 7GB in cache out of 16GB total:

 

Shouldn't the OS clear the cache before killing processes?

I wonder if the Folder Caching plugin I run has something to do with it.

If it's a one time thing you can ignore, if it keeps happening try limiting more the RAM for VMs and/or docker containers, alternatively a small swap file on disk might help, you can use the swapfile plugin:

 

https://forums.unraid.net/topic/109342-plugin-swapfile-for-691/

It's about a once-a-month thing.

 

Apparently I had a very superficial understanding of linux memory allocation.

 

I've installed the plugin, fingers crossed.

 

The problem is usually not just about not enough RAM but about fragmented RAM, swap file can help with that.

I've only seen OOM errors while running a 4GB VM (in addition to my standard apps.)

I haven't booted that VM since installing the plugin.

But now that swap's available unRAID is using it.

 

Interesting.

 

 

 

 

Edited March 8, 20233 yr by CS01-HS

The weekly scheduled boot of the VM that's caused this went off last night without a hitch – 2GB swap used (out of 4GB.)

If it goes smoothly next week I'll mark this as solved, thanks.