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Re: scsi & ide disk speeds?



Svante Signell wrote:
Hi,

-SNIP- <

However, with DMA off the speed is very low:
hdparm -d 0 /dev/hda
/dev/hda:
 Timing buffered disk reads:  64 MB in 15.26 seconds =  4.19 MB/sec


I got just about the same answer(s) on my machines when I ran hdparm on them. ALL of the machines were defaulting to DMA off. This all started when a visiting "guru" complained about the slow FTP transfers over my home LAN. Upon investigation, I found the HD I/O on the various machines was capping the max transer rate of large files (330 Mbyts or so) to about 14% (14 Mbs)of the rated capacity (100 Mbs) of the network between any two machines! Turning DMA on on all machines rasied this value dramatically to around 50% of the rated capacity between any two machines!

> -SNIP-<
BTW: Is there a good place to put in the hdparm -d 1 /dev/hda
somewhere at the boot scripts? I've added it to the
/etc/init.d/bootmisc.sh script. It would be very nice to have this as
default without making any manual changes, but I assume there are
reasons why not.


There is a Debian package called "hwtools" that creates a nice initscript located in /etc/init.d/ that is called during bootup. There is a place to place this command in there. I just discovered this and implimented it here. It works like a charm! You get a few other "tools" in the process, most of which I havn't used yet.

Cheers,
-Don Spoon-



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