[mythtvnz] Recording dropouts and disk performance...

[Rob Connolly]

On Sun, Feb 17, 2013 at 04:36:38PM +1300, Chris Bannister wrote:
> On Sun, Feb 17, 2013 at 10:26:36AM +1300, Rob Connolly wrote:

<snip>
 
> > However, when I try to probe for DMA support I get the following, on
> > both disks:
> > 
> > /dev/sdb:
> >  HDIO_GET_DMA failed: Inappropriate ioctl for device
> 
> Yeah, I get that too. Don't know why.
> 
> > I'm pretty sure something is not right here, since DMA is a pretty basic
> > feature!
> 
> Seems to be a thing called UDMA now.
> 
> But if you use the '-i' switch you should see, e.g.
> 
> root at tal:~# hdparm -i /dev/sda
> 
> /dev/sda:
> 
>  Model=Hitachi HTS541040G9AT00, FwRev=MB2OA61A, SerialNo=MPB2PAXHDBZZUM
>  Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
>  RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
>  BuffType=DualPortCache, BuffSize=7539kB, MaxMultSect=16, MultSect=8
>  CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=78140160
>  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=yes: mode=0x80 (128) WriteCache=enabled
>  Drive conforms to: ATA/ATAPI-6 T13 1410D revision 3a:
>  ATA/ATAPI-2,3,4,5,6
> 
>  * signifies the current active mode
> 

Yep, I get it looks like it is something to do with SATA disks, since
DMA is always enabled [0]. I get:

/dev/sda:

 Model=WDC WD20EARX-008FB0, FwRev=51.0AB51, SerialNo=WD-WCAZAD986001
 Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs
FmtGapReq }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=0
 BuffType=unknown, BuffSize=unknown, MaxMultSect=16, MultSect=16
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=3907029168
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio3 pio4 
 DMA modes:  mdma0 mdma1 mdma2 
 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6 
 AdvancedPM=no WriteCache=enabled
 Drive conforms to: Unspecified:  ATA/ATAPI-1,2,3,4,5,6,7

 * signifies the current active mode

And:

/dev/sdb:

 Model=WDC WD20EARX-00PASB0, FwRev=51.0AB51, SerialNo=WD-WCAZAA880394
 Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs
FmtGapReq }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=50
 BuffType=unknown, BuffSize=unknown, MaxMultSect=16, MultSect=16
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=3907029168
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio3 pio4 
 DMA modes:  mdma0 mdma1 mdma2 
 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6 
 AdvancedPM=no WriteCache=enabled
 Drive conforms to: Unspecified:  ATA/ATAPI-1,2,3,4,5,6,7

 * signifies the current active mode

> 
> In fact, the '-I' switch (need to pipe through less) shows more info
> than you probably need.
> 
> Those timings look OK, but maybe others on the list can help out with
> their info for comparison purposes. Looks like the disks are OK.
> 

Glad you think the disks are OK! I was thinking (and hoping) the same
thing. Thanks for your help.

Cheers,

Rob

[0] http://ubuntuforums.org/showthread.php?t=844717