DMA Mode of Hard Drive

Ace2005 · 07-14-2005, 03:32 AM

Hi

Its been bugging me all week, the speed at which files are coppied is very slow and i think its due to the DMA mode that linux is using, how do i find out the DMA mode that is in use and then change it.

Motherboard supports UDMA Mode 6

Hard Disk 1 - UDMA Mode 6

Hard Disk 2 - UDMA Mode 5

Hard Disk 3 - UDMA Mode 4

CDRom - UDMA Mode 2

Anyone else notice that hard disk access in linux is slow?

Brian Knoblauch · 07-14-2005, 06:59 AM

I find it to be very fast, but all of my current systems are SCSI...

mdg · 07-14-2005, 07:27 AM

As root in terminal, type "hdparm -i /dev/hdxx", where hdxx is the disk you want to check. This command will tell you what DMA modes are available for the specific disk and which mode is being used. It also spits out other relevant info

You can also do "hdparm -tT /dev/hdxx", which will give you some data read speeds for the disk.
This is the result on my disk for reference:

Code:

/dev/hda:
 Timing buffer-cache reads:   2268 MB in  2.00 seconds = 1131.91 MB/sec
 Timing buffered disk reads:  136 MB in  3.02 seconds =  45.08 MB/sec

vibrokatana · 07-14-2005, 01:23 PM

hdparm can set the settings i believe typing in hdparm will give a nice long list

im not sure if "rc-update add hdparm boot" is needed to keep the settings, when its added it says something about configuring drives during boot up

on my server i get about 62MB/sec w/ my hitachi 160gb sata

comprookie2000 · 07-14-2005, 02:46 PM

Here is some information on hdparm;
http://forums.gentoo.org/viewtopic-t-319349.html
Look for;
4. Configure Your Hard Disk

Ace2005 · 07-20-2005, 04:46 AM

These results don't look too good

I also rearranged the hard disks, tried some other distros, then reinstalled with Fedora, its the only distro which i like (so far).

--==-----------------------------------------------------------==--

-------==Hard Disk 2 - UDMA Mode 5==-------

/dev/hda:
Timing cached reads: 836 MB in 2.01 seconds = 416.19 MB/sec
Timing buffered disk reads: 40 MB in 3.07 seconds = 13.04 MB/sec

/dev/hda:
multcount = 16 (on)
IO_support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 256 (on)
geometry = 39560/16/63, sectors = 20416757760, start = 0

-------==Hard Disk 3 - UDMA Mode 4==-------

/dev/hdb:
Timing cached reads: 820 MB in 2.01 seconds = 408.02 MB/sec
Timing buffered disk reads: 30 MB in 3.09 seconds = 9.71 MB/sec

/dev/hdb:
multcount = 16 (on)
IO_support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 256 (on)
geometry = 25228/16/63, sectors = 13020069888, start = 0

-------==Hard Disk 1 - UDMA Mode 6==-------

/dev/hdc:
Timing cached reads: 832 MB in 2.00 seconds = 415.65 MB/sec
Timing buffered disk reads: 56 MB in 3.07 seconds = 18.22 MB/sec

/dev/hdc:
multcount = 16 (on)
IO_support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 256 (on)
geometry = 65535/16/63, sectors = 81964302336, start = 0

--==CDRom - UDMA Mode 2==--

/dev/hdd:
Timing cached reads: 840 MB in 2.00 seconds = 419.64 MB/sec
Timing buffered disk reads: 8 MB in 3.08 seconds = 2.59 MB/sec

/dev/hdd:
IO_support = 0 (default 16-bit)
unmaskirq = 0 (off)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 256 (on)
HDIO_GETGEO failed: Invalid argument

--==-----------------------------------------------------------==--

It looks like all the hard disks are using UDMA mode 2 to me

Ace2005 · 07-21-2005, 07:23 AM

Ok everything is back to normal after i enabled S.M.A.R.T in Bios