[mythtv-users] Hard Drive Performance

[Ryan Steffes]

>
> 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.

/dev/hda:

 Model=ST3200822A, FwRev=3.01, SerialNo=3LJ1APBB
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs RotSpdTol>.5% }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
 BuffType=unknown, BuffSize=8192kB, MaxMultSect=16, MultSect=16
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=268435455
 IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio1 pio2 pio3 pio4
 DMA modes:  mdma0 mdma1 mdma2
 UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
 AdvancedPM=no WriteCache=enabled
 Drive conforms to: ATA/ATAPI-6 T13 1410D revision 2:

/dev/hdc:

 Model=ST3250823A, FwRev=3.02, SerialNo=5ND064BR
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs RotSpdTol>.5% }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
 BuffType=unknown, BuffSize=8192kB, MaxMultSect=16, MultSect=16
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=268435455
 IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio1 pio2 pio3 pio4
 DMA modes:  mdma0 mdma1 mdma2
 UDMA modes: udma0 udma1 udma2
 AdvancedPM=no WriteCache=enabled
 Drive conforms to: device does not report version:


So perhaps the CD is blocking the UDMA5 mode and that's what's borking me?
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