RE: hdparm / DMA problems - options
hi ya
On Sun, 10 Aug 2003, Nyc0n wrote:
-- if you dont know hwo to use hdparm ...
you stand to corrupt data on your disks
> Well, here is my script file, the first two drives are connected to the
> MB, which doesn't support DMA so I left out the -d1 parameter on those,
> the other 4 are connected to my Promise UltraATA133 Tx2 card, which does
> support DMA....
>
> hdparm -q -X34 -u1 -m16 -c1 -a16 /dev/hda
> hdparm -q -X34 -u1 -m16 -c1 -a16 /dev/hdb
> hdparm -q -X34 -d1 -u1 -m16 -c1 -a16 /dev/hde
> hdparm -q -X34 -d1 -u1 -m16 -c1 -a16 /dev/hdf
> hdparm -q -X34 -d1 -u1 -m16 -c1 -a16 /dev/hdg
> hdparm -q -X34 -d1 -u1 -m16 -c1 -a16 /dev/hdh
-X34 means you are using (very old) dma mode ( dma2 )
== and you wonder why its slow ??
-X66 is ata33 ( udma2 )
-X68 is ata66 ( udma4 )
-X69 is ata100 ( udma5 )
-X70 is ata133 ( udam6 )
- i dont use -a16 ... ( readahead options )
> /dev/hda:
> DMA modes: mdma0 mdma1 *mdma2 udma0 udma1 udma2 udma3 udma4 udma5
says this disk supports udma5 ( ata100 )
you've downgraded your disk down to mdma2 w/ hdparm instead of udma5
> using_dma = 0 (off)
says you should turn on dma mode in the kernel if -d1 didnt work
when hdparm was manually invoked
> /dev/hdb
> DMA modes: mdma0 mdma1 *mdma2 udma0 udma1 udma2 udma3 udma4 udma5
you've downgraded your disk down to mdma2 w/ hdparm instead of udma5
> /dev/hde:
> DMA modes: mdma0 mdma1 *mdma2 udma0 udma1 udma2 udma3 udma4 udma5
you've downgraded your disk down to mdma2 w/ hdparm instead of udma5
> using_dma = 1 (on)
magic ... that ide controller is supported by the kernel
....
>
> Here are some speed tests after it boots with the script.....
>
> /dev/hda:
> Timing buffer-cache reads: 128 MB in 1.35 seconds = 94.81 MB/sec
> Timing buffered disk reads: 64 MB in 14.95 seconds = 4.28 MB/sec
the only number you (should) care about is "buffered disk read"...
> /dev/hdb:
> Timing buffer-cache reads: 128 MB in 1.34 seconds = 95.52 MB/sec
> Timing buffered disk reads: 64 MB in 15.06 seconds = 4.25 MB/sec
>
> /dev/hde:
> Timing buffer-cache reads: 128 MB in 1.34 seconds = 95.52 MB/sec
> Timing buffered disk reads: 64 MB in 9.19 seconds = 6.96 MB/sec
even w/ dma supported by the kernel and disk drives, you told it to run in
mdma2 ...
which is exactly what you're getting
c ya
alvin
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