[ale] Just an FYI for those using UDMA hard drives and RH 7.2

[Michael Smith]

I have been fighting for the last 2 weeks trying to get my 7.2 machine up 
for more than 12 hours at a time without a kernel panic and I think I 
finally got it working...

I determined that it was a UDMA issue after receiving {DriveStatusError 
BadCRC} errors in the messages log file.  So I bought 2 new 80 pin, less 
than 18 inch, ide cables after reading this blurb at 
http://www.kernel.org/pub/linux/docs/lkml/#s13-3 .  I still received the 
errors.  So I then moved the hard drives to the bottom and top bays to 
hopefully reduce any crosstalk.  Still didn't work.  I then moved the power 
cables as far away from the ide cables as possible.  Still didn't work.

So now I am thinking that either my controller or my hard drives are bad.  
I go to the Maxtor site and download Powermax to test the drives.  I 
perform exhaustive checks with both drives coming out without any errors. I 
am now at a loss.  

So I dig a little more on the Maxtor site about the write verify 
functionality on the hard drive and find out, that for speed, the write 
verify is turned off after 10 power cycles on the hard drive.  So I 
downloaded this utility called WVSet from their site and turned the write 
verify back on permanently and now my machine has been up for 24 hours w/o 
a kernel panic....

Here's Maxtor's blurb on Write Verify:

"Write Verify" performs a Read of the data just written to the hard drive 
and validates the data via the Cyclic Redundancy Check (CRC), providing 
additional assurance that the data written to the hard drive was written 
correctly. When Write Verify is enabled, the WRITE performance of the drive 
is affected as a read occurs for each write. When disabled WRITE 
performance is improved as, a read is not performed for each write
When performing benchmark operations the "write verify" feature should be 
disabled to insure valid comparisons to other products that do not offer 
this capability in their product.


Just an FYI......

-- 
Michael Smith



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