I also had some very bad experience with pfense performances in a virtual environment.
Under Proxmox any kind of network load have an abnormal impact on cpu load, often almost freezing the host.
On esx it's a bit better but at the cost of low throughput.
From what I've read it's an issue with offload/checksum with FreeBSD.
After lots of digging on the subject I gave up and switched to VyOS for my proxmox cluster. It doesn't have a nice web panel but the load of the host is now barely noticeable.
4-5 years ago I used pfsense as internet gateway and vpn for point to point in an office with probably 20-30users.
We had it clustered between a VM (on ESXi) and a physical appliance on alix (if I recall correctly, or another of the supported sff appliances). The VM was rock solid while the appliance from time to time was experiencing issues (stuck/memory exhausted I think) up to the point that DHCP lease were not released anymore and the office was de facto unable to work.
I think at the end we just kept the VM running alone.
I don't on my FreeBSD hosts and haven't had any problems, but I think it depends on the drivers you have installed. On all my production servers I use standalone Intel NICs w/ the Intel drives; pfSense may be using something else depending on the configuration. FWIW, pfSense has been basically stock FreeBSD + software/skin for the past couple of years.
I've used pfSense in VirtualBox for years, as VPN-gateway VMs. I'm posting from a VM that hits the Internet through three VPNs in a nested chain. Each pfSense VM uses just ~70MB.
There's not an appliance per se but you can just install it to a virtual machine. I was running a 1 CPU, 256MB instance with a 100mbs line and noticed no issues - ESX running on Core i7-920
I really thought they had a blog post somewhere or maybe a tweet or something stating they were planning to support a vm, but I'm failing to find the link. Maybe I'm remembering incorrectly. In any case, they do have a forum section dedicated to virtualization:
Under Proxmox any kind of network load have an abnormal impact on cpu load, often almost freezing the host. On esx it's a bit better but at the cost of low throughput.
From what I've read it's an issue with offload/checksum with FreeBSD.
After lots of digging on the subject I gave up and switched to VyOS for my proxmox cluster. It doesn't have a nice web panel but the load of the host is now barely noticeable.