Why does a system suddenly start hanging ... ?

[Marc G. Fournier]

A couple of months ago, I decided to take a chance and went SATA for one 
of our servers ... all others in the past have always been SCSI ... now, 
all of a sudden, the SATA server is *hanging* ... using tw_cli to look at 
the controller, and the drives and controller all appear to be well ... 
fsck finds the file systems to be good ... but after a period of time (an 
hour, maybe two) of running, the server  grinds to a halt, and I have to 
get it rebooted and start all over again ...

The server is an Intel SE7520 motherboard, with a 3Ware 9500S-4LP 
controller, and 3 ~126G hard drives ... operating system is RELENG_4 from 
~May 22nd ...

And none of the log files that I can think to look at are reporting any 
problems or errors :(

So ... what causes an SATA system to 'hang'?  If it was a SCSI system, it 
feels like the same thing that woudl be attributed to a bad cable or 
termination ...

----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy at hub.org           Yahoo!: yscrappy              ICQ: 7615664