Very high system load writing data to SCSI DVD-RAM

[Oliver Feiler]

Hello,

	I have the following problem with a DVD-RAM drive. The drive is a 
Panasonic LF-D101 connected to a Tekram DC395U SCSI controller. Kernel is 
2.2.18 with the patch for the Tekram controller 
(http://www.garloff.de/kurt/linux/dc395/). 

	When I write huge amounts of data to a DVD-RAM the system load is 
getting very high, like 10 or even above and the system temporarily freezes 
for a short time every minute or so while writing data to the drive. The DVD 
drive writes data with 1.35 MB/sec on the discs so there is not really much 
data going over the SCSI controller. Reading data from DVD-RAMs is done with 
2.7 MB/s (2x) by the drive and does not cause any problems at all.

	This problem also existed with previous kernels (2.2.16/17) and with 
another SCSI controller I had before the Tekram. Adaptec 2904CD using the 
aic7xxx driver.

	There is a 4x Teac burner connected to the SCSI controller as well. 
Burning CDs does not raise the system load or cause any other problems.

Bye,
Oliver

-- 
Oliver Feiler                                               [e-mail]
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