Plant, Dean wrote:

...

Simple fix,

Adaptec & CentOS = :-( LSI & CentOS = :-)

Which is why after a few hours of testing I decided to indeed buy a couple of LSI cards to test with -- far better than a lot of frustration.

But, meanwhile, I decided to test one more thing: just suppose that the SCSI auto-negotiation, which worked fine before, had suddenly given up in version 3.0 of the aic79xx driver?

I forced the transfer rate in the Adaptec BIOS for those IDs to the maximum that my Infortrend could support (U160) and for good measure disabled "Disconnect" as well. Then, rebooted into 2.6.18-8.1.6&8, and it worked: User==Goal==Curr==160.0 MB/s. Apparently, the latest aic79xx driver V3.0 does no longer support auto-negotiation, whereas all drivers <=1.3.11 did negotiate correctly.

Michael, maybe that works for you as well (unless your tapedrive actually does do U320)?

I did the same (changed the speed in the BIOS settings) and it's working. I tried it at 80 but I think I'm going to bump it to 160 and see if it works.

I still wish I could figure out why the adaptec kernel driver won't install though. Maybe I'll try downloading the source and manually compiling the kernel module.