[UCI-Linux] 3ware <-> USB & KDE conflict on AMD64-SMP (Kubuntu)?

[Harry Mangalam]

Hi All,

Here's an interesting data point - hopefully almost to the end of my degrading 
experience with 3ware / AMD64Linux / Western Digital / hotswap cages / 
Dual Opteron / Kubuntu / etc.

All 8 x 250GB disks are up and running on the 3ware 9500S-8, in repaired 
hotswap cages, filesystem is XFS (better io by 30-50% than ext3 by both 
bonnie++ and usage and much less CPU utilization).   All the disks passed 2 x 
smartctl long tests before being put into service and there have been no 
complaints from them or the 3ware since they spun up.  

However, I have discovered an interesting glitch in all the hardware swapping 
I've done:
When running Ubuntu/Kubuntu AMD64-SMP (and only SMP) on both 2.6.10-5 and 
2.6.11-1 kernels, the 3ware controller prevents the USB from working 
correctly.  This isn't a killer issue for us, but it would be nice - we run a 
UPS that communicates via USB and a sysadmin would like to use the machine 
for his USB Palm cradle.  
Additionally, when KDE starts up, it frequently locks up the system (easy 
solution - remove KDE; it's a server, no loss), but this would seem to be a 
serious flaw with one of KDE, 3ware, or AMD64-SMP. 

Consider this a single data point that might be wrong, but it's easily 
repeatable on our IWILL DK8X mobo.

With the onboard 4-port Silicon Image controller and a $20 Syba/Silicon Image 
4 port PCI controller, I had no such problems when I was hot-testing the 
disks and in SW RAID.  Both USB and KDE worked as advertised.  It doesn't 
appear to be an interrupt conflict, but I guess I could move the 3ware to 
another slot at next reboot.

Anyone see anything like this?

Resources (many of them dated but they give good background on the issues):
http://pcbunn.cacr.caltech.edu/gae/3ware_raid_tests.htm 
   - dated, but better than most in terms of trying different tuning tricks
http://bioinformatics.org/pipermail/bioclusters/2002-August/000367.html
http://www.3ware.com/LInuxSell_0629.pdf 
   - mostly marketing, but some useful info
http://www.3ware.com/Linux2.6WP_0701.pdf 
   - much more info, less marketing
http://oss.sgi.com/archives/linux-xfs/2005-05/msg00157.html 
   - and the thread that follows; very close to my hardware situation
http://oss.sgi.com/projects/xfs/papers/filesystem-perf-tm.pdf 
   - dated but a lot of useful info in one place
http://www.tweakers.net/reviews/557/5
   - extensive review of SATA controllers; 
     highly recommended if you're in the market for HW SATA RAID


-- 
Cheers, Harry
Harry J Mangalam - 949 856 2847 (vox; email for fax) - hjm at tacgi.com 
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