[mythtv-users] Diskless backend?

[Tupshin Harper]

Max wrote:

> I've been pondering going diskless on front AND backend (store all 
> data on NAS). The frontend is easy and I am sure plenty of people are 
> doing it, however I am wondering how practical is it on the backend. 
> At around 4GB per hour with higher quality, it works out to be about 
> 8Mbits/s worth of raw data. Add overhead and all and double for 
> playback, this will clearly not work with 10baseT and wireless, but 
> theoretically should not be an issue on a "no-collision-domain" 
> 100Mbit (I think the figures I seem to recall is about 40Mb/s 
> sustained data transfer on 100Mbit copper, a bit more on fiber. Plus I 
> am wondering if NFS can even handle this sort of the data without 
> severe load increase on the server and client.
>  
> ... or I could be overly paranoid and it may work just fine.
>  
> Anyone played with this sort of a setup? Any experiences?
>  
> -M

I haven't done a diskless myth-backend, but my frontends are diskless, 
and I've done plenty of other diskless implementations. If you have a 
switched 100BT setup, bandwidth will certainly not be an issue. Latency 
could be (e.g. response time when skipping forward or backward through a 
live recording), but shouldn't be that bad if your myth-backend NFS 
mounts the NAS volumes with the nosync option(this used to be the linux 
default, but was changed relatively recently to default to sync to 
correspond to industry norms). I can't swear that this would help, it 
relies a bit on implementation details of myth that I'm not familiar 
with, but I would lay pretty strong odds that performance would be adequate.

-Tupshin