[mythtv-users] Drive specs best for Myth

[Kevin Kuphal]

Brian Wood wrote:
> Kevin Kuphal wrote:
>
>   
>> Actually, one drive (root) is on the main IDE controller as master.  The 
>> CD-ROM is on the secondary main IDE controller as master.  80-conductor 
>> cables all round.  The other two drives are on a PCI IDE controller each 
>> on their own channel as master.  Hdparm info seems identical across all 
>> drives (220MB/sec for the first measurement, 60MB/sec for the second)
>>     
>
> Sounds like you have the drives set up as well as you can with IDE/ATA
> drives. I just mentioned the common setup problems because they are,
> well, common.
>
> I haven't done the math, but you may simply be pushing the limits of
> what consumer-type disk I/O on a 32-bit PCI buss can do.
>   
That surprises me as I figured I didn't have nearly the uber-setup that 
some people might have.  I did offload /var to another 80GB disk running 
as slave on the primary IDE channel last night so I'm hoping that takes 
away enough IO from the primary master which holds both root as well as 
part of my LVM array for recordings.  My suspicion is that the IO back 
and forth between the HD streams and the logging/database might be too 
much.  Just offloading the DB before didn't do enough but then my logs 
are fairly active.
> You may be able to get some marginal improvement by looking at PCI
> latency, you also might increase the niceness level of the commflag
> jobs, but that's CPU niceness, not I/O system "niceness".
>
> There was something on this list many many months ago about decreasing
> the I/O priority of a job.
>   
Thanks, I'll have to look into that as well as Yeechang's suggestion.  I 
saw another post yesterday about changing the dirty write buffers which 
I may also try.  I didn't want to have to look into other disk systems...
> Obviously going to a server type motherboard with 64-bit SCSI disk
> controllers and disks would likely solve your problems, but at what is
> most probably a prohibitive cost.
>   
Certainly.  Would moving to SATA make any difference here?

Kevin