I have a couple virtualized fileservers running in QEMU/KVM on ProxmoxVE. The physical host has 4 storage tiers with significant performance variances. They're attached both locally and via NFS. These will be provided to the fileserver(s) as local disks, abstracted into pools, and handling multiple streams of data for the network. My aim is for this abstraction layer to intelligently pool the tiers. There's a similar post on the site here: Home-brew automatic tiered storage solutions with Linux? (Memory - SSD - HDD - remote storage) in which the accepted answer was a suggestion to abandon a linux solution for NexentaStor. I like the idea of running NexentaStor. It almost fits the bill. NexentaStor provides Hybrid Storage Pools, and I love the idea of checksumming. 16TB without incurring licensing fees is a huge plus as well. After the expense of the hardware, free is about all my budget can handle. I don't know if zfs pools are adaptive or dynamically allocated based on load, but it becomes irrelevant since NexentaStor doesn't support virtio network or block drivers, which is a must in my environment. Then I saw a commercial solution called SmartMove: http://www.enigmadata.com/smartmove.html And it looks like a step in the right direction, but I'm so broke I'd be wasting their time to even ask for a quote, so I'm looking for another option. I'm after a linux implementation that supports virtio drivers, and I'm at a loss as to which software is up to it.