[mythtv-users] Virtualisation .. can it do this? (HP ProLiant MicroServer N40L)
linux at thehobsons.co.uk
Tue Sep 25 16:09:20 UTC 2012
>I have noticed, from forums etc, that almost everyone who owns one
>of these things uses some sort of technology to run different
>virtual OS's on it. I couldn't really see the point of this unless
>you are either a developer or an uber-geek (a term I use with the
>greatest respect .. I am a merely a semi-geek). It just sounds to me
>like there's more that can go wrong than if I was just running the
>machine with a standard OS. And I had heard that USB tuners could be
>a headache to get working in a virtual machine.
>I hate things that don't just work these days and can't bare the
>headache when things go wrong (I must be getting old!)
>However, I did have a thought this morning.
>One thing that constantly trips my up with Mythbuntu is
>upgrading/updating it. I know a lot of you would say, if it's not
>broke, don't fix it. But I like to have the latest stable version of
>So, my question is, could virtualisation help with this?
Yes, but I think it's probably overkill for what you want.
I bought one of the earlier N36L Microservers, with the intention of
running MythTV and my other services on it. However I found that my
tuners (PCIe, HVR-1300) didn't work with Xen loaded and more than 4G
of physical RAM in the machine. Didn't work as in, in Dom0 they were
recognised but any attempt to tune anything returned no data.
Since they were still on cashback I bought another for everything
else and kept one just for Myth.
What I'd suggest is rather than going for virtualisation, use LVM for
everything but a /boot filesystem*. Then it's fairly simple to just
create additional LVs, clone your current system over to them
(remembering to tweak things like /etc/fstab), and then reboot into
the newly made copy. Your original remains safe and sound while you
experiment - and when you are ready you can just make the new version
your live system by setting the default boot entry in grub.
* If you do keep a physical partition for /, then you may want to
keep another spare one for your tests.
Obviously you need to keep enough spare room in your LVM VG for any
extra volumes you might need.
This does have the downside that you have to shut down your live
system while working on the new one - but as long as you keep an eye
on the schedules/upcoming recordings then it should be too hard to
find reasonable windows to work in. On the other hand, since you'll
probably need your hardware (tuners etc) for some of the
testing/setup then you'd still need to shutdown your live system even
if you were running full virtualisation.
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