arcmsr & areca-1660 - strange behaviour under heavy load

From: Nikola Ciprich
Date: Sat Feb 23 2008 - 06:30:45 EST


Hi,

I've found strange problem either in arcmsr driver, or maybe in areca-1660 card...
When system on SAS discs RAID connected to areca-1660 card gets under heavy I/O load, it gets unusable after some time. I can 100% reproduce this, although it needs quite speciffic conditions:
It can be reproduced on 2x quad core machine, RAM has to be limited to ~192MB to cause heavy paging.
Only thing needed to cause the problem is to start loop doing kernel compilation using make -j 8 - this loads the system heavily, because of lack of memory. After few correct compile runs the system gets into state when all programs including the basic ones (ls, cp, ..) start crashing... dmesg (when it works) doesn't say anything strange...
After reboot, the system is OK again.
I have tested it on different motherboards, with different CPUs, RAMs(all were properly tested with memtest), with two different areca cards and different drives. I can't reproduce the problem on same hardware when using different RAID card (ie adaptec). All testing systems were properly cooled..
I have tried all available areca firmwares, two different distributions (oracle linux, and centos), and kernels ranging from distribution ones, to last GIT snapshot.
Could somebody please give me some hints on how to hunt this problem?
Areca support doesn't seem to be very interested in the problem :-(
Thanks a lot in advance
BR
nik

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Nikola CIPRICH
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