Proxmox VE

From my own experience, I believe Proxmox VE to be very well suited for small businesses that need a virtualisation solution without breaking the bank. You can start off with the free edition and that might very well be all you need. If you do require a paid plan, there are multiple plans to choose from, to suit most budgets. This isn't to say it not's suitable for medium and large businesses, but I have no personal experience of it at that scale. Organisations with experience of Debian and/or Ubuntu based systems, will feel right at home straight away. The base OS is mostly unchanged from upstream so things generally just work as you'd expect them to. One scenario that might make you think twice about Proxmox VE, is if you have already standardised on non-ZFS storage, such as hardware RAID. Although I'm sure this can be made to work, Proxmox really shines when used in combination with ZFS.

Proxmox VE is a virtualization platform that provides a range of features and functionalities suitable for various scenarios. Here are some specific scenarios where Proxmox VE is well suited and some scenarios where it might not be the best choice:Well-suited scenarios:Virtualization of server workloads: Proxmox VE is well suited for virtualizing server workloads such as web servers, mail servers, database servers, and other similar applications. Its high-performance virtualization capabilities allow these workloads to run smoothly and efficiently.Hosting multiple virtual machines (VMs): Proxmox VE is ideal for hosting multiple VMs on a single server. It provides efficient resource management, allowing users to easily allocate resources to each VM.Clustered environments: Proxmox VE is a great choice for clustered environments. It supports clustering and can easily manage multiple servers, providing high availability and load balancing for mission-critical applications.
Less appropriate scenarios:
Limited hardware resources: Proxmox VE requires significant hardware resources to run efficiently. If you have limited hardware resources, it might not be the best choice.
Simple applications: If you only need to run a single, simple application, Proxmox VE might be overkill. Other virtualization platforms or even a basic web hosting service might be more appropriate.

For testing lab and home, PVE does not require a license, with the easy use web interface, easy use firewall, it can run without manager. With the KVM virtual engine, the performance will not degrade than bare. Totally, it is suitable for low cost, easy management environment.

We used Proxmox to implement private cloud services, for clusters of a small number of servers, from 3 to 11 with and without high availability. Allways with ZFS file systems, and we used to install the root pool in SSDs mirrored and use other pools with RAID 10 in groups of four, for the virtual machines and containers, for the backups and snapshots, we used magnetic disks with RAID 10, in groups of four. Do not use an even number of servers because does not facilitates the implementation of High Availability, because the corosync service must have an odd number of servers to detect a failed server for the quorum system. We used a variety of servers, from clone PCs with AMD Ryzen with 6 cores and 12 threads with 64 GB of RAM no ECC, to high end servers with 64 cores and 128 threads per cpu and 2 cpus per server, with AMD EPYC Rome or Milan, 2 terabytes of RAM ECC.

We've been able to deploy Proxmox and easily migrate machines to and from the environment. This has proven invaluable as each of our clients is unique. One great example was when a client had some mishaps with VMWare. The environment became difficult to use due to some licensing issues and we were easily able to export the VMDKs and import them into Proxmox.

Another interesting situation that Proxmox really shines is with integration with snapshot based filesystems (like ZFS). We have ZFS shares with snapshots exported to Proxmox via NFS. When we need to recover an individual file from the VM, rather than needing to copy the entire snapshot back, we can log into Proxmox via SSH and use the CLI to mount the disk from the snapshot. Then we can copy just the data we need out. Because this happens outside of the virtual machine and on a completely separate network, it is protected against ransomware and malicious users. It also is super convenient.