Diagnosing a hung VM, Bhyve? What to do.

[Patrick M. Hausen]

Ubuntu. Current server LTS, so 20.04 at the moment. Just a single Ext4 filesystem, redundancy, snapshots, etc. are provided outside the VM via ZFS obviously. I feel most at home with Debian style distros.

 

[diskdiddler]

I'm using Ubuntu 20.04 but I'm afraid this problem has reached critical in the last few days, she's hung again. So my urge to migrate to the proxmox machine is increasing significantly.



I had such a good run over all for a while too.

 

[diskdiddler]

That's possibly your best bet...
cu -l /dev/nmdm19B

Well I never
By logging in, this method it seems to have woken the machine up from a hung state. Load was 17 at the time, as I logged in. I wonder if python what python was doing at the time.

 

[Patrick M. Hausen]

Are you using the server variant of Ubuntu? If the VM can be woken by typing anything at the serial console, I suspect desktop power saving "things" might be to blame here ...

 

[diskdiddler]

Are you using the server variant of Ubuntu? If the VM can be woken by typing anything at the serial console, I suspect desktop power saving "things" might be to blame here ...

I'd agree with you if I still ran Desktop (this is exactly why I bit the bullet, realised I'm capable of using server now) about .... 10 months ago.
It's also how I learnt that Ubuntu server has a tiny tiny tiny bit more latency than desktop
https://i.imgur.com/mPCpBYQ.png (it's about half a millisecond)

 

[diskdiddler]

Why are you using AHCI virtual disks? You should run disk and network as VirtIO devices when running Linux or FreeBSD guests.

I have only just noticed this reply, apologies.
How does one address this, is it difficult?

 

[Patrick M. Hausen]

Check your guests /etc/fstab - if that contains only UUIDs for partitions instead of device names, you should be able to just shutdown, reconfigure, boot. You can always change it back if it does nor work as intended. Everything else is more a Linux than a TrueNAS question/problem. Sorry, you will have to do some disk diddling

 

[diskdiddler]

Check your guests /etc/fstab - if that contains only UUIDs for partitions instead of device names, you should be able to just shutdown, reconfigure, boot. You can always change it back if it does nor work as intended. Everything else is more a Linux than a TrueNAS question/problem. Sorry, you will have to do some disk diddling

Do you think this could be impacting stability?
Bear in mind, this machine was solid for 18 months?

I really want to migrate her over to Proxmox but I'm pretty sure it's not as simple as a ZFS send to Proxmox sadly.
Would I need VirtIO drivers, for Proxmox or another solution?

 

[Patrick M. Hausen]

Do you think this could be impacting stability?

As far as I'm concerned all my VMs use VirtIO and all have been rock solid for years.

I really want to migrate her over to Proxmox but I'm pretty sure it's not as simple as a ZFS send to Proxmox sadly.
Would I need VirtIO drivers, for Proxmox or another solution?

Sorry, I never used Proxmox and I doubt I ever will. My alternative to TN CORE for virtualisation is ESXi.