[mythtv-users] My First MythTV Box

match at ece.utah.edu match at ece.utah.edu
Tue Jan 1 00:22:15 UTC 2008

I wrote:

> > 3. At this time I don't see much value in having the system/DB on a  
> > separate
> > disk, do you?

To which Brad answered:
> Not true!
> I've often sent praises to heaven that I have a 60GB system drive  
> separate from my tv recordings drive. I've had system drives die more  
> frequently than video storage drives due to the mysql activity on it.  
> Also, because of the high disk activity with small transactions in  
> mysql all the time, I can tweak that drive to perform better on lots  
> of small drive activity and use larger blocks and buffers on my video  
> storage drives.
> My first myth system had a single 250GB drive in it. I had constant  
> recording/playback glitches due to /var being on the same drive as my  
> video storage. One I put it on a separate IDE channel, I had no more  
> problems and never looked back.
> My recommendation is a small manageable, easy to back up system drive  
> and a gigantic video drive.

And Mike answered as well:

> Wrong!
> It is an *extremely* sensible idea to separate your system files and your Mythtv 
> files onto separate disks. *Especially* to put the Mysql database on a separate 
> disk to the video storage. When recording there are many I/Os to the video disk 
> at the same time as many I/Os to the Mysql database. You really don't want to be 
> thrashing your heads from one file to another at the rate video comes in.
> For the system disk you don't even need 80Gb, but if that's what you got, go 
> with it.
> Mike Perkins

OK, Brad and Mike, I understand full well where you're coming from, and I 
used to think this way too... back when. Many years ago I subscribed to this 
very logic, but not anymore, and I've done it both ways. Modern SATA 300 
drives are faster, cheaper and more reliable than drives were back then, so I 
just no longer see the need.

Perhaps I've just been lucky, but I've never lost a system disk in any of my 
Mythboxen, and I've never encountered I/O throughput problems by having 
the Mysql database on the same drive that I store recordings on. These have 
just never been issues for me over these last 4 or 5 or so years that I've 
been running MythTV.

Now that I've said that, I'll probably suffer a drive failure, but for heaven's 
sake guys, they're only TV shows, and there will be more of them even if I 
lose a whole diskful. And if I lose the system, well it's probably time to 
upgrade to newer versions anyway.

Therefore, I contend that the cost (in heat, power and noise) does not justify 
the benefit gained by dedicating a drive position to a tiny drive that only holds 
the system and the database. That realestate is better used by installing 
another large drive, chosen to maximize the GB per buck ratio, IN MY 

I guess I would be willing to meet you half way. Use the extra space on the 
system disk for something else. Something non-critical, like backing up and 
serving other computers in the house, but even in this configuration the 
80GB drive is too small to be useful and the 500GB is barely adequate, from 
my experience. So we're back to 2 large drives... The cost in dollars for 
another 500 is only a little more than double the cost of the 80, if that, and 
will likely perform better.

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