bhyve current windows status

[Robert Crowston]

nvme is faster than virtio-blk? It seems strange that a paravirtualized driver would be slower. Is that because of the regression you mention?

— RHC.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Sunday, 11 April 2021 04:49, Jason Tubnor <jason at tubnor.net> wrote:

> Hi Matt,
>
> Further to Peter's input below, I have added what we have in production for
> Windows Server 2016/2019
>
> On Fri, 9 Apr 2021 at 16:30, Peter Grehan grehan at freebsd.org wrote:
>
> > > What are the current recommended devices/options for Windows (2019
> > > server in my case) - especially with ZFS. Should I be specifying a
> > > 512/4096 sector/block size via bhyve and/or zfs? I assume nvme &
> > > virtio-net are the current best options but is there a preferred virtio
> > > driver version. Are any of the other virtio drivers of any use to be
> > > installed or just the network drivers?
> >
> > nvme - yes.
>
> If using 12.2 or greater, NVMe across the board for guests. We will be
> switching over once we bring the fleet of appliances up to 13.0 upon
> release.
>
> If you are using 11.4, virtio-stor is your only option if you are after
> performance. While you can use ahci-hd, this is shockingly slow. About 2
> versions ago of the VirtIO stack users of the virtio-stor drivers saw a
> regression in the driver take out whole virtual storage devices. Running
> the latest one as at 11 April 2021 should be fine for you.
>
> > I'll leave the sector/block size issues to others. I don't touch any
> > of those params but don't use enough Windows apps to make a qualified call.
>
> We set volblocksize=4k for all guests unless the guest is running MSSQL, in
> which case, volblocksize=512. We have observed significant storage
> consumption when using this smaller block size, likely due to the checksum
> overhead for small amounts of committed data.
>
> No need for other virtio drivers. For virtio-net, the recommendation
>
> > is to use the latest one.
> >
> > > Are there any known problems with applications like AD/Exchange? I know
> > > that SQL 2012 had massive storage overhead issues on ZFS due to 512 byte
> > > writes, but I'm not sure if that still affects newer versions or other
> > > applications?
> >
> > As above, I'll leave it up to others to chime in here.
>
> Yes, that still applies. It is clear that you have discovered what we have
> (as also what I typed above for others to reference). I don't believe that
> has been fixed by Microsoft yet. I may get around to testing against newer
> versions over the next couple of months.
>
> Cheers,
>
> Jason.
>
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