Best overprovisioning settings for this setup?

[gogito]

So I'm setting up a small homelab on a PC:
CPU: Intel Xeon E31268L v3 - 4 cores 8 threads - Around an i7 4770 in performance
RAM: 16GB DDR3
SSD: 128GB mSata => Boot and VMs
HDD: 2x8TB HDD
1Gbps Network

I'll install Proxmox on that and set up these VMs:
1. OpenMediaVault 6 with the 2x8TB HDD passthrough => Running in Stripe with SMB
2. DietPI - Running Emby getting content from OMV
3. DietPI - Running piHole
4. Ubuntu 21.10 VM

I want to best utilize my hardware, especially for Emby for those random 4k media that needs transcoding. I thought of 2 ways:

1. Max everything
- Set all VM to 8 vCPU and 16GB RAM and let Proxmox manage their usage. piHole shouldn't use much nor will OMV, mostly Emby and Ubuntu will but I read some information about context switching and how hypervisor needs all 8 CPUs to be available for Emby 8 vCPU to function well and therefore needs to wait (For example if piHole is using 1 of its CPU) .... Not sure if these info are still correct or relevant.

2. Custom
- OMV gets 4GB RAM and 2vCPU
- piHole gets 1GB RAM and 1 vCPU
- Emby gets 12GB RAM and 8 vCPU (Or 6 if one of the problem like context switching I described in 1 actually matter)
- Ubuntu gets 8GB RAM and 4 vCPU

I know I can use LXC for some of the stuff like Emby, piHole, .... but I just like VMs more since it really separate everything in the system.

 

[Dunuin]

You can't overprovision the RAM. That will always cause problems. If you only got 16GB RAM, don't assign more than 13 or 14GB to all your VMs combined. Overprovisioning the CPU works fine as long as you don't overdo it. If you only got 4 real cores I wouldn'T give a single geusts more than 4 vCPUs and not more than maybe 16 vCPUs in total (maybe 32 vCPUs if they are all idleing all the time).