[PVE-User] Limited number of virtio-devices/drives

Emmanuel Kasper e.kasper at proxmox.com
Mon Aug 3 10:02:26 CEST 2015

> We currently have a customer evaluating a system with 16 x 12Gb/s SAS
> drives driven by an HBA. They have intentions of building systems with
> 24 bays and 24 SAS drives.
> Maybe we are going about this all wrong and perhaps there is a smarter
> way to do this....however....
> The customer's software is based on FreeBSD/NAS4Free. This runs on
> Proxmox VE as a VM.
> The VM's conf file looks like this snippet:
> virtio0: /dev/sda
> virtio1: /dev/sdb
> virtio2: /dev/sdc
> virtio3: /dev/sdd
> virtio4: /dev/sde
> virtio5: /dev/sdf
> virtio6: /dev/sdg
> virtio7: /dev/sdh
> This is to allow the software to see the drives in the GUI and also to
> provide max performance....we think. We are also considering PCI
> passthrough options to have the VM see the HBA card directly.
> The FreeBSD system will then use these drives to create a zpool.
> With a limit of 16 Virtio disks, it seems that we can't use this
> approach to operate 24 disks.
> Any suggestions? Any creative approaches to work around this problem?

Hi Keri
The FreeNAS folks have a good post on how to virtualized FreeNAS, most
of it will apply to Nas4free and KVM.


Don't be scare by the title, it does work, but you have to pay great
attention to what you are doing ( I am myself having such a setup)

As Michael and the FreeNAS folks says you absolutely  have to PCI pass
through your storage controller, as ZFS expects to have access to the
real device.


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