Re: NetBSD/xen 9 motherboard recommendations

[Brad Spencer <brad%anduin.eldar.org@localhost>]

Alaric Snell-Pym <alaric%snell-pym.org.uk@localhost> writes:

> [1:multipart/mixed Hide]
>
>
> [1/1:text/plain Hide]
>
> On 16/10/2022 18:03, Brad Spencer wrote:
>
>> The answer will depend on your goals, needs and budget.  However, this
>> last week I went though a system change.
>
> I figured the odds of somebody having recently built a system with the 
> same goals, needs and budget as me were pretty minimal, so I'm happy to 
> extrapolate from what I can get!
>
>> I think I will be happy enough with the replacement, although I do note
>> that the replacement uses more CPU in DOM0 when I/O is going on, so it
>> appears to be less balanced.  NetBSD 9.2_STABLE from 2022-06-16 or so
>> worked just fine with Xen 4.15.1 from pkgsrc 2022Q2. 
>
> Perfect! Duly noted, thanks :-)

Having run with this board for a few days I have a couple of other
observations:

1) The BMC really does work pretty well in it, except if you want the
Java KVM.  In that case you will have to use a Java 8 version 121 or
below.  It seems that anything after that probably won't function.  I
was able to use a build of OpenJDK and it worked fine.  The reason that
this may be of interest is that the Java KVM allows you to redirect
CDROM, images and floppy disks but the HTML5 KVM only allows for CDROM.
This may or may not matter to your use case, of course, just something
to note.

2) The motherboard supports a COM port as a 10 pin header, but they
didn't send a DB9 with the board to bring it out and make it useful.  I
had a DB9 to 10 pin from something else that will nearly work and it
appears that this type of arrangement has developed into a standard of
sorts (the pin outs are available in the board documentation).  The
reason this may be interesting is that the BIOS and the BMC supports
pretty nice and pretty complete serial port redirection.  It also seems
that if you enable that ability you can use "ipmitools sol ..." to get
access to the console too.  All of this may be useful depending on your
use case.

3) With the processor I am using I noted that with 9.2_STABLE, the DOM0
would spend a whole lot of Xen CPU time (xentop -d 1) when lots of
activity was going on.  I added a dual NIC to the box, so there are 4
NIC ports and it is loaded with 4 SATA drives in two raidframe mirror
pairs.  A raidframe rebuilt would run CPU on the DOM0 to about 100%.
This problem appears to pretty much go away by using a -current kernel.
The reason could be because -current can use MSI for interrupt handling
in Xen, and does for a number of the devices, or it could be other
optimizations.  So, I am currently running Xen 4.15.1 with a 9.99.101
DOM0 kernel (and /stand modules), and a 9.2_STABLE userland.  The only
gotcha right now is that -current knows about the dwiic device that is
present on the motherboard, but the driver doesn't support the chip
variant and panics on boot.  The simplest thing to do is compile a
kernel without dwiic or use userconf to disable it on boot.



I am generally pretty pleased with the set up.  It seems to work well
for a small Xen server and should be fine in the role that it is
intended for.



-- 
Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS - http://anduin.eldar.org