[mythtv-users] Mythtv FE in a frequent power loss environment

[James Crow]

Jason Spears wrote:
>
>
> On Tue, Dec 8, 2009 at 6:42 AM, Rajil Saraswat <rajil.s at gmail.com 
> <mailto:rajil.s at gmail.com>> wrote:
>
>     Hi,
>
>     I would like to setup a front-end in an environment where power
>     failure are a norm. The plan is to have a UPS for the backend so that
>     it cleanly shutdown but the frontend will be on its own.
>
>     So is it ideal to go for a diskless frontend (nfs mounted backend)?
>     What happens when FE is alive and a power failure occurs, will it
>     corrupt the backend filesystem.
>
>
> It doesn't directly address your question, but would an Ion based 
> netbook be a good fit here?  No UPS required, short outages can be 
> survived, and you can setup automatic shutdown on low battery.
>
> Does a mythtv FE need to write to the recordings / videos 
> directories?  If not, I'd just mount ro and not worry about it at 
> all.  My uneducated guess is that the only thing a FE should need to 
> do is update the current position as a recording is watched.
>
> Jason
>
> ------------------------------------------------------------------------
>
>   
I do not mount my recording directories by my FE machines. They stream 
TV through the myth protocol from the BE. I know 0.21 could not do that 
for videos, but that may be fixed in 0.22.

What about taking this one step further and creating a LVM snapshot of 
the powered off network booting FE. Every time the machine boots it 
reverts to the snapshot so no changes are stored between boots, but for 
a FE I think that would be ok. I actually had a car computer doing 
something like this in 2003 or so. I actually mounted my / filesystem as 
read-only. It worked well except when I needed the log files. I had to 
copy them off before shutting the machine down. AFAIR /tmp and /var were 
mounted to RAM drives. My init scripts had to create a skeletal /var 
directory structure. A RO / would be perfect for a netbooting FE. No 
concerns about power loss. All important info is stored on the server.

Cheers,
James