[mythtv-users] Mythbacked on ESXi 5.0
raymond at wagnerrp.com
Mon Oct 24 16:08:51 UTC 2011
On 10/24/2011 11:39, Tim Draper wrote:
> since the majority of the time, both my windows and mythtv installs
> are idle, then why not stick them on the same hardware?
If you use Windows for basic web browsing and email, then why are you
not just running Linux in the first place? If you use Windows for
things like games, or other applications that only work on Windows and
use a lot of power, then chances are you are going to need access to
resources that you cannot get through a VM, and your system load would
be disruptive to MythTV anyway.
The big consequence of migrating multiple primarily idle servers into
one machine is that their loads tend to be bursty. If those bursts
occur at different times, everything is great. The applications get
everything they need, and couldn't care that they're sharing the
hardware. If those bursts occur simultaneously, resource bottlenecks
mean they both take more than twice as long. This is one of the big
reasons why it is recommended not to run mythbackend on a machine used
for a desktop, where an active user may cause a lot of IO and CPU load
browsing the web. The other is that users tend to do usery things that
result in loss of system stability.
> also, and possibly the one everyone would find the most useful;
> migration. you can stick it on any hardware and the guest will be the
> same as it was, without fear of having to recover or ammend the
> existing install.
I don't see how this is something exclusive to virtual machines. MythTV
doesn't store any configuration information outside the database, so it
is inherently portable. Change the IP address registered in the
database as the master, and now you've just promoted one of your slave
backends. Run the utility in the backup tool to alter hostnames, and
now you've brought all your configuration information from your previous
system. If you want true portability, make an ISO, loop mount it,
chroot in, and install MythTV and all its dependencies into there. One
way or another, it's never going to be painless because you will always
have to migrate your storage and recording hardware.
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