On 2019-11-22 19:53, Jes wrote:
On Fri Nov 22, 2019 at 9:04 PM Dumitru Moldovan wrote:
Supported guest operating systems are currently limited to OpenBSD and
Linux. As there is no VGA support yet, the guest OS must support serial
console.
Speaking of this, does anyone here have any experience running Linux VMs
on vmm/vmd? I threw Alpine/Debian installs together recently and
they seemed to work well. Looking for anyone with longer-term experience
as I'm interested in setting up a VPS hosting service on vmm/vmd, and
would appreciate any advice or anecdotes.
I have some Alpine and Void Linux installs running on vmm. They work
well, with some caveats.
You may have issues with your VMs clocks. OpenBSD guests in vmm are now
able to use the pvclock driver, which has greatly improved time keeping
on my VMs, although I still do have some erratic clock jumping, but at
least it's not so bad that ntpd can't keep up with it.
However the timekeeping situation for my Linux VMs is bleak. On both
Void and Alpine, no clocks are even detected. In the dmesg it complains
about the TSC clock source being unstable. Ultimately, we're left with
only jiffies as a clock source option:
void$ cat
/sys/devices/system/clocksource/clocksource0/available_clocksource
refined-jiffies jiffies
As a result, my clocks run at about one third of real time.
I've tried the Linux VM's on both an old Xeon machine as well as a
modern Ryzen machine, and the clock situation seems to be equally bad on
both of them.
...
Clock issues aside, I've found Linux guests to get better networking
throughput on vmm than OpenBSD guests.
A few results from benchmarking Alpine vs Void vs OBSD, with iperf3:
(vmm host is older xeon rig, iperf3 tester is ryzen desktop)
Alpine got this result:
[ ID] Interval Transfer Bitrate
[ 5] 0.00-10.00 sec 511 MBytes 429 Mbits/sec sender
[ 5] 0.00-8.60 sec 511 MBytes 499 Mbits/sec
receiver
Void Linux Got this result:
[ ID] Interval Transfer Bitrate
[ 5] 0.00-10.00 sec 611 MBytes 512 Mbits/sec sender
[ 5] 0.00-7.00 sec 610 MBytes 732 Mbits/sec
receiver
And OpenBSD got this result:
[ ID] Interval Transfer Bitrate
[ 5] 0.00-10.00 sec 299 MBytes 251 Mbits/sec sender
[ 5] 0.00-10.19 sec 299 MBytes 246 Mbits/sec
receiver
Because folks always freak out when tcpbench is forgotten about, I
tested tcpbench as well between the two machines running OpenBSD:
Peak Mbps: 231.240 Avg Mbps: 204.423
I know that was some very unscientific testing, but hey, you asked for
anecdotes.
Cheers,
Jordan
