[mythtv-users] Two-backends with two-frontends on one machine?

[Michael T. Dean]

On 07/11/2007 11:27 AM, Steven Adeff wrote:
> 1) RAID 1 seems like overkill, why not go with RAID5? I've got a 6
> drive RAID 5 device that keeps up with my 4 HD tuner backend with two
> HD capable frontends no problem.

And, in the future (i.e. 0.21 and up), RAID may in fact work against
you.  With Storage Groups, you can set up your system to write each
recording to a separate disk (provided enough disks), thereby
significantly reducing fragmentation and seek issues.  I have 4 HDTV
capture cards and more drives than capture cards and have configured
Myth so that it will only write two shows to the same disk if that's the
only way to record the show (i.e. if all the other disks are full). 
After using it this way for some time, I can say I'll never use a
multiple-disk (RAID or LVM with multiple physical volumes) configuration
with Myth again.

(Granted, with N capture cards and N or more RAID's, you can get the
same reduction in fragmentation and seek issues, but, really?)

> I can see your point about hardware failure (motherboard, CPU, RAM,
> etc) with a single machine though. I think its a rare enough
> occurrence though that perhaps having spare parts on hand may make
> more sense if your that worried.
>   

And, if using a single system with master/slave backends and the master
fails, it's easy enough to "promote" the slave to a master (assuming
availability of the DB or a DB backup) while getting parts to fix the
broken system.  And, while the recordings on the broken system are not
available, you just can't watch them (and Myth won't have issues with
their non-availability).

Mike