[mythtv-users] Hard Drive Performance

Ryan Steffes rbsteffes at gmail.com
Thu Mar 30 16:38:52 UTC 2006


On 3/30/06, Tom Lichti <tom at redpepperracing.com> wrote:
>
> Ryan Steffes wrote:
> >
> >
> >     Your buffered reads look more or less normal, but your cached reads
> >     are less than half of what they should be. I get over 1900 MB/sec.
> >     for cached reads.
> >
> >     Are you sure DMA is enabled for your drives ?? Was the system doing
> >     anything else when you ran the tests?
> >
> >     You never want to put a hard drive on the same IDE bus as an optical
> >     drive, it will slow the HDD down to the (probably 33) speed of the
> >     latter. You should put both of your hard drives on the primary IDE
> >     channel. This, however, does not explain the slow speed of your
> /dev/
> >     hda drive, but it would explain problems with /dev/hdc.
> >
> >     Make sure you are using a proper 80-conductor cable for your hard
> >     drives as well, you need to be running in UDMA mode to get top
> >     performance (assuming your Motherboard has a modern IDE interface,
> >     without that you're pretty much dead in the water).
> >
> >
> > The system was recording during that test, I can shut myth down later
> > to get "clean" numbers if it would help.  DMA is on for both drives.
> What does hdparm -d /dev/hd? show?


/dev/hda:
 using_dma    =  1 (on)

/dev/hdc:
 using_dma    =  1 (on)
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