[geeks] OS testing, dragonfly

[Shannon]

On Sep 10, 2011, at 15:33 , vintagecoder at aol.com wrote:

>> SMP: There are no easy ways to verify SMP is working. From dmesg output
>> it appears that dfly is not seeing both of my CPUs. I may have to build a
>> kernel for that, not sure. AMD64 support is newer than the 32-bit stuff.
>
> If you are running on a box that doesn't have the virtualization extensions
> in some cases you may not get smp support even though you actually have
> a multicore host.

This is a Mac Pro so it does have the support. Other OS see multiple CPUs all
the time. I suspect maybe the default kernel for DragonFly didn't have SMP
support, or maybe it is incompatible with Fusion.

> There is a way to check via top whether the system is using more than one
> cpu. I can't remember what the option is on BSD, on Linux you just type 1
> (one) while top is running to toggle it. man top and you should find it
> quickly.

There is none in DragonFly, or it is disabled if the system did not detect two
CPUs. Usually dmesg shows dual CPUs. Only one kernel, so either its
incompatible with VMWare Fusion, or its disabled by default.

DragonFly uses modular kernels and I don't see any SMP modules. I also don't
see many cpu tools like cpuctl in NetBSD, which can verify SMP operation among
other things.

cpuid is there and only shows one CPU so I assume that means its just not
there.

Testing data migration from Solaris to DragonFly at the moment, to put a good
data load on Hammer filesystem. I love the automatic snapshotting,
master/slave, and other features.

> Thanks for your writeup on Hammer. Lots of good info in there.

The more I play with it the more I like it. It definitely is not for every
situation in its default "save everything" state, but that can be tuned.

I'm tempted to forget running a VMM and just run this until I can afford more
hardware to play with.

The VMM decision really boils down to each solution I see lacking something I
really want.

NetBSD is missing SMP support and a nice filesystem to set it all upon (like
ZFS or Hammer). I could groan and moan and forget the filesystem but the lack
of SMP sucks. Also its harder to configure than anything else and lacks the
latest Xen.

Linux Xen is very mature and fast, and the tools are extensive and very
mature. However, the major vendors have dropped support for it. You have to
build the tools yourself and modify the base install to put Xen support back
in. Linux lacks a nice filesystem like ZFS or Hammer. BRTFS just scares me at
present, which is a shame because ZFS and Hammer gives you far easier
management.

Linux KVM tools are very mature, and setup is easy. KVM is not as mature as
other solutions yet but is still very good. It has major vendor support. Same
filesystem issue. KVM also requires HVM support which not all my servers have.
Once I get more money I'll care about that less, but I still prefer lighter
guest OS installs when possible.

Solaris KVM is an unknown so can't comment on that. I don't thin I'm going to
test that, if I go KVM I'll just use Linux.

If I just had one more quiet server this would be easier: I could migrate and
keep playing. I'm really interested in seeing where Xen goes now with
mainstream Linux kernel support and increasing use of version 4. DragonFly's
cluster and VMM future looks good too, but that's probably a ways off.












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