[mythtv-users] Mythbacked on ESXi 5.0

Richard Stanaford rstanaford at gmail.com
Mon Oct 24 17:10:05 UTC 2011

On Mon, Oct 24, 2011 at 11:27 AM, Raymond Wagner <raymond at wagnerrp.com> wrote:
> So where does this get you with MythTV?  The home user isn't doing
> anything that is going to be bothered too much by the occasional crash.
> The home user isn't going to have hot spare systems to fail over to in
> the event of a hardware failure (and the free ESXi doesn't allow such
> anyway).  With all its runtime information stored in the database,
> MythTV is already fairly close to the "elegant solution".  Change the IP
> address of the master backend, and with a few keystrokes, a slave
> backend gets promoted to master and you can start back up.
> There is a time and place to run VM software, but like Govindarajan, I
> don't see a home user running MythTV to be one of them.  If you find it
> fun and amusing, or even just good practice for a career, have at it.  I
> just don't see how it can make management and operation an easier task.
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You are presuming the "home user" has access to all the hardware they
need.  In most cases, they don't.  I am going to construct an iESX
server to host a number of VMs, most of which will not need to run
concurrently, but each has their own set of requirements that make
them too disparate and impractical to run on a single device.  Such
needs included, but are not limited to...

- A development environment
- A VM hosting the corporate base install image from my employer
(domain registration, certificates, etc.) for work.
- An experimental network environment utilizing DynaMIPS/Dynagen/GNS3
- VMs for each of my four children.

None of those applications justifies dedicated hardware (the kids in
particular), even if I had the funds available to allocate.  Plus,
having the OS for each VM isolated to a single file that I can
snapshot in my sleep makes, "Daddy, my computer won't start anymore",
or, "My term paper is gone", scenarios easier to deal with.

I was under the impression that the whole impetus behind the
development of virtualization was to consolidate the many, the
disparate in to one footprint.  "Reduce your management, reduce your
expenses and footprint on the environment, let virtualization do it
all for you!"

Well, let it do it all, then.  Say you build a dedicated back end.
How many clock cycles are wasted with it just sitting there between
recording/transcoding sessions?  Even with a multi-core processor
grabbing analog streams with hardware-based encoders on the cards, the
processors are going to be bored.  The only question is how well can
the VM see the cards through the hypervisor and how efficiently that
data can be sent across the bus to the disks?  Multi-disk database
architectures run on virtualized environments all day, every day.

Your question, Raymond, was "why bother at all?"  Well, virtualization
platforms vendors (like Oracle with their VirtualBox product) are
beginning to experiment with D3D support.  Why bother with that?
What's the purpose?  Obviously for better CAD/CAM support, but
historically hasn't there always been dedicated and specialized
hardware for such endeavors as well?

Seems that some of those lines are being blurred these days.  In the
home arena, it's financially more practical in most cases.


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