[mythtv-users] Dvd archive setup

Rod Smith mythtv at rodsbooks.com
Sun Mar 4 17:10:08 UTC 2007

On Sunday 04 March 2007 09:55, Mike Jacks wrote:
> I have a front-end/back-end already setup. I'm wanting
> to setup a back-end server to hold my dvd collection.
> I don't want to have the box running all the time to
> save the life of the hard drives.

There's some debate about whether or not this would actually save disk life; 
the stress of turning the disks on and off may be greater than the stress of 
leaving them running 24/7. There were a couple of recent big studies on disk 
life released, one from Google and one from another source (I don't recall 
exactly who it was). I haven't studied either, I'm afraid, so I don't know 
what, if anything, they say on this issue. You might want to look into it, 

> I just want to turn 
> it on when i want to watch a video, then turn it back
> off. I was wondering what would be the best setup for
> this? Would i just run a standard back-end and turn it
> on when i want to and the front-end/back-end would see
> it no problem?

If the ONLY purpose of this machine is to be a big disk farm to hold 
recordings (that is, if you don't want to put a tuner in it), then you 
wouldn't configure it as a MythTV backend at all. Instead, you'd set up a 
file server (NFS or Samba) on the machine and configure MythTV to mount its 
exports (for NFS) or shares (for Samba; same concept, different terms) on 
your MythTV frontend(s) in an appropriate location. You should then be able 
to store and access videos automatically.

The trouble is that if you take your file server down frequently, as you say 
you want to do, the directories will become inaccessible on the frontend. 
This won't cause the frontend to crash or anything, but it could cause delays 
and even hang processes when performing some actions, such as when using 
the "df" command or, most importantly, when shutting down. One way around 
this would be to unmount the file server's exports/shares before shutting 
down the file server. This would be easy to overlook, so if you decide to 
shut down your file server frequently, you might consider setting up a script 
that first unmounts the exports/shares on the frontend and then shuts down 
the file server. You could run such a script on the frontend and have it 
telnet into the "shutdown" account on the file server. This account usually 
exists but is disabled. If you enable it, it'll shut down the server whenever 
it's accessed; it's designed for exactly this sort of situation. You'd then 
need to mount the file server's exports/shares when you start up the file 
server. Automounting might take care of this, but I haven't tried it with 
network exports/shares.

Instead of shutting down the file server, you might want to look into 
power-saving tools (ACPI, etc.). My knowledge of these is limited, though, so 
I can't offer much guidance.

If you want what you've called your backend to have a tuner and record shows, 
you'll still have to configure exports/shares to have it store DVD images, 
but you'll also have to configure it as a MythTV backend. Depending on how 
you do it, you might or might not need to set up a reverse file sharing 
configuration to let the backend save its recordings on your frontend. 
Shutting down a true backend on a regular basis is probably a bad idea, 
unless its tuner is used infrequently and you regularly check your upcoming 
recordings to know when you'd benefit from having it running.

Given all these issues, not to mention the extra expense of running an entire 
computer just to hold videos, I'd probably just stick extra hard disks in the 
combined frontend/backend system. The main reason I can think of not to do 
this would be if the extra noise, or possibly size or heat, would be an 
issue. Note that external drive enclosures are pretty common, so if your 
existing case isn't big enough, you could use one of these. You might even be 
able to tuck it someplace unobtrusive, if aesthetics are an issue.

Rod Smith

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