[mythtvnz] Recording dropouts and disk performance...

[Chris Bannister]

On Sun, Feb 17, 2013 at 10:26:36AM +1300, Rob Connolly wrote:
> 
> Here is the hdparm output for both disks:
> 
> /dev/sda:
>  Timing cached reads:   3074 MB in  2.00 seconds = 1536.81 MB/sec
>  Timing buffered disk reads: 332 MB in  3.00 seconds = 110.54 MB/sec
> 
> /dev/sdb:
>  Timing cached reads:   3052 MB in  2.00 seconds = 1526.28 MB/sec
>  Timing buffered disk reads: 342 MB in  3.01 seconds = 113.48 MB/sec
> 
> /dev/sda:
>  multcount     = 16 (on)
>  IO_support    =  1 (32-bit)
>  readonly      =  0 (off)
>  readahead     = 256 (on)
>  geometry      = 243201/255/63, sectors = 3907029168, start = 0
> 
> /dev/sdb:
>  multcount     = 16 (on)
>  IO_support    =  1 (32-bit)
>  readonly      =  0 (off)
>  readahead     = 256 (on)
>  geometry      = 243201/255/63, sectors = 3907029168, start = 0
> 
> 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


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.

-- 
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who are being oppressed, and loving the people who are doing the 
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