# Hot-Add virtual drives on FreeBSD 10



## bigb89 (Mar 1, 2014)

Hello guys,

I am running KVM on a Centos 6.5 host and have a few VMs running, including a FreeBSD 10 virtual machine.

For my virtual machines, I am using VirtIO for the disks as that allows better disk performance as well as the ability for me to to hot-add drives to VMs. From checking the release notes on FreeBSD 10, it has native support for VirtIO:  http://www.freebsd.org/releases/10.0R/relnotes.html

From my FreeBSD virtual machine I do see that all the required virtio modules are indeed in there:


```
root@bmi1:~ # kldstat -v | grep virtio
                448 virtio_pci/virtio_scsi
                447 virtio_pci/virtio_balloon
                446 virtio_pci/virtio_blk
                445 virtio_pci/vtnet
                444 pci/virtio_pci
                443 virtio
```

I am able to add VirtualIO block devices (disks) to the FreeBSD 10 VM, however, my problem is that I cannot hot-add them. The FreeBSD VM needs to be rebooted for the OS to see the new drive. Now, I find this weird as I am able to hot-add virtIO drives to all of the other OSes (even windows) and the OS will see the new drive right away without the need to reboot it.

So my question is: Has anyone been able to hot-add virtIO disks to FreeBSD VMs, and have the OS see the new drive without a reboot? If so, any special instructions for it?

Please let me know if any additional info is needed.

Thank you in advance.


----------



## minimike (Mar 20, 2015)

BUMP same problem here with an FreeBSD 10.1 Guest and OpenStack Juno with KVM powerd.


----------



## junovitch@ (Mar 20, 2015)

Does `dmesg` show any events when the device is added and does `camcontrol rescan all` help by forcing a device rescan?


----------



## mav@ (Mar 22, 2015)

With VirtIO drivers each disk is separate PCI device. As I understand, the only hot-plug possible there is PCI hot-plug, which AFAIK is still not very supported. Though I haven't tested it yet.


----------

