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Memory usage at 100% and system crashes

Posted: 28 Apr 2019 22:41
by bgold
I am running 12.0.0.4.6625 on fairly high performance hardware.

I have 256gb ram, dual processor, 3 zfs pools with ssd cache drives.

I have been using virutalbox for a ubuntu vm and the NAS is crashing when memory usage reaches 100%.

I have reached the recommended settings for ZFS and kernel and applied some.

I can't keep the system running for more than a day without it crashing.

I understand that FreeBSD uses all available memory for cache and is supposed to free up as needed.

Not sure if there are any settings to keep a certain amount of memory available for the vm.

Any help would be appreciated.

Let me know what information is needed to help in troubleshooting.

Thanks

Re: Memory usage at 100% and system crashes

Posted: 28 Apr 2019 23:25
by JoseMR
You no longer need to bother with "vm.kmem_size", instead limit the "vfs.zfs.arc_max" , to check if the max target has been applied use "sysctl vfs.zfs.arc_max"

with all that much RAM you have, maybe I would free up at least ~6G depending on how many VM's you have and how much RAM you've reserved for them and test, between if this is a panic, check if you can read something like "kmem_malloc" or something alike on the console/BMC.

I also assume that you have at least a 2GB Swap partition on the boot ssd?

Regards

Re: Memory usage at 100% and system crashes

Posted: 28 Apr 2019 23:30
by bgold
The vm is 65gb. I have 10gb swap on ssd. I will remove vm.kmem_size and set vfs.zfs.arc_max and free up 65gb and see if that helps.

Thanks

Re: Memory usage at 100% and system crashes

Posted: 29 Apr 2019 07:24
by raulfg3
vfs.zfs.arc_max=32 is enough for enterprise use.

what value do you set?

Re: Memory usage at 100% and system crashes

Posted: 29 Apr 2019 16:25
by bgold
I have it set to 192gb. Since doing the changes yesterday it has been at 92% not any higher and the system did not lock up or loose connection with the VM. I will change it to your recommendation if that is what it should be at. I have ssd drives for cache/logs. 3 pools are there any other tweaks that I should make in the sysctl.conf file?

Thanks