[OpenIndiana-discuss] Slow performance of guests in virtualbox on OI?

[Jim Klimov]

Hi,

   I don't think I've had substantial lags in VBoxes, but it may
be a lucky case of hardware - and that's not only the different
layers of virtualization support in CPUs. In particular, recent
list mails suggested that server-grade NICs with buffers and
networking-task offload features might implement things like
CrossBow VNICs with their unique MAC addresses in hardware
rather than with CPU emularion and brute promiscuous mode.
Likewise, I believe it might be possible to find such hardware
that would lag due to HW or (lack of) drivers in illumos, and
you might have had bad luck with that on a particular motherboard.
Thus, you might have better luck with separate NICs, usually
those with e1000g driver pose almost no problems (during OS
upgrades, they forget the Jumbo settings, if those were used,
due to overwriting of /kernel/drv/e1000g.conf).

   To verify that you hit VBox-intrinsic problems rather than
something else, can you:

1) Set up an etherstub on the host and attach VM VNICs to that?
This should rule out any hardware from your networking between
VMs and host, leaving the VM engine performance and limitations.
If this does work for you better than equivalent setup on
hardware, you can organize routing/NAT via the host GZ or a
dedicated LZ with exclusive IP stack attached to this etherstub.

2) You did set up the MAC addressing for bridged VM interfaces
properly, right? (You have a dedicated host VNIC per VM NIC,
and the unique MAC addresses of the two are equal)
I did not really work with non-bridged interfaces (VBox NAT,
VBox host-only), so can't comment on performance of those.

3) Recent VBox might add some optimizations like "memory
balooning" and memory deduplication. I wonder if these happen
to you, and if they are troublemakers or not...

4) Do you use the proprietary extension pack above the GPL VBox
software, and do you add guest additions to your VM's OSes?
Usually, these should help speed up your VM experiences.

5) Look in VBox logs (stored under VMs' folders), to see if the
engine complains about anything unusual that it can't initialize
or use, etc.

6) Scroll over VirtualBox under Solaris forum, perhaps ask some
questions there too :)

On another hand, I don't think I've stressed my systems that much.
Basically, for an interactive VM I've only used my laptop in the
past few months, and when there were tests with a dualbooted Win7
(on its dedicated partition where it could native-boot from too)
performance felt acceptable. It did take slower to boot and halt,
that with a native boot, but after I added RAM (and about 3Gb of
the 8Gb available got dedicated to the Windows VM), performance
during work (word processing, browsing) was not really discernible
from that with a native boot with 4GB HW RAM before. Windows is
memory-greedy however, so anything around 2GB lagged even on HW
native boots for Win7 and Vista.

For virtualization purposes, you might also need to provision
much swap space (at least as much as your VMs are configured to
use as their vRAM), and disk performance/cache for the backing
stores might matter - though you do say that is blazing fast.