I know that I can pass through an entire disk to a VM (and I've done this with no issue), but I'm wondering what the actual benefit is to doing that? Is the read-write to the disk faster that way? Why not just create LVM or ZFS disks on the host and attach virtual disks to the VM? Seems like this allows for more flexibility in terms of how the disk can be used down the road.
benefit to passing through entire disk?
- Thread starter mccclxxxv
- Start date
In the end that isn't a real passthrough and the disk is virtualized too because there is still something like virtio in between the physical disk and the guest.
But it might still be useful in some cases. Lets say you want a TrueNAS VM as your NAS. TrueNAS will use ZFS inside the VM and its a bad idea to run ZFS ontop of ZFS because of the exponential overhead that would produce. Here it is nice to have the ability to "passthrough" the disks using "qm set" if it isn't possible to use a real PCI passthrough because no unused HBA is available.
But it might still be useful in some cases. Lets say you want a TrueNAS VM as your NAS. TrueNAS will use ZFS inside the VM and its a bad idea to run ZFS ontop of ZFS because of the exponential overhead that would produce. Here it is nice to have the ability to "passthrough" the disks using "qm set" if it isn't possible to use a real PCI passthrough because no unused HBA is available.
