RH Enterprise hdparm using_dma is off.

Miwa · 05-04-2004, 10:52 AM

Hi,

I am using RH Enterprise(WS) kernel-2.4.9 and I have question about hdparm settings.

Does anyone know why 'using_dma' is set to '0 (off) ' as default? It is making the system slow down quite a bit. Is there risk to keep 'using_dma' on? I would like to keep the DMA set to ''ON''. But once the system is rebooted, it sets back to 'OFF'. I think in RH 7.3, DMA is set to ''ON'' as default. Why did it changed to ''OFF'' as default? And how to set it up so that DMA will stay ''on'' after reboot?

Could anyone help me with this?

Thanks
Miwa

Crashed_Again · 05-12-2004, 05:18 AM

I had a similar problem with hdparm in Gentoo. It turned out to be a problem with kernel configuration. Check your kernel configuration again. Also, I'm not sure where it is in RedHat, but /etc/conf.d/hdparm has the default settings for hdparm on my Gentoo box.

320mb · 05-12-2004, 08:55 AM

EXAMPLE:

Code:

hdparm -d 1 -c 3 -k 1 -S 253 /dev/hda

the -d 1 flag sets DMA to "on"
the -c 3 flag sets the I/O to 32-bit/ with sync
the -S 253 flag sets the Vendor Specific spin down time.
AND the -k1 flag keeps these settings intact between reboots....
read up on the different flags, options..........
man hdparm
in Slackware all this goes into........./etc/rc.d/rc.local