Re: Slow performance on DomU

[Miguel Clara <miguelmclara%gmail.com@localhost>]

There's a custom compiled kernel "XENHVM" wich add the PV drivers to
FreeBSD HVM domu's and this will give you better performance.

Check: https://wiki.freebsd.org/FreeBSD/Xen

Specially this part:
"Notes on PV drivers

In addition to emulating physical devices, Xen supports
para-virtualized drivers, which provide better performance and
integration. FreeBSD supports the netfront (network interface),
blkfront (storage device), and Xen console devices. These devices can
be probed and attached if xenpci is configured into the kernel.

The netfront driver attaches as its own ethernet driver, xnX.

The blkfront driver attaches as a block storage device, but emulates
the adX and daX disk namespaces used by the ATA and SCSI drivers based
on the disk number presented by Xen."


You should be able to find more info on google on how to compile
XENHVM kernel for Freebsd-9 amd64

 But, if I'm not missing something this should be the steps to do it
(assuming you already have src):

cd /usr/src
make buildkernel KERNCONF=XENHVM
make installkernel KERNCONF=XENHVM

Then make sure to change the device names for network and disks, has
the note says...

Meaning: /etc/fstab --> change "ada0" to "ad0"

And you're network config... If you're using /etc/rc.conf, just change
"ifconfig_re0" to "ifconfig_xn0"

Reboot!


Hope it helps!