mpt_sas driver bottlenecks badly with single misbehaving disk on controller
While burning in a set of 106 drives, I noticed the following fascinating behavior.
I would normally get blazing-fast performance out of the system, but occasionally everything would just stop responding to keyboard requests or any queries about the pool for over a minute. The activity lights would also go idle.
It turned out this behavior occurred whenever certain disks were plugged into the backplane.
dmesg fills with the attached excerpt ad-infinitum until disk is removed.
Updated by Rich Ercolani about 10 years ago
One last snippet I should have included - the controllers are two LSI 9201-16e and a 9201-16i. Behavior has been observed on both. All running latest (as of writing) firmware (BIOS: 7.17.00.00; FW: 9.00.00.00). Backplanes are from two SC847E26-RJBOD1 chassis, headnode with the controllers in it is an SC836E26-R1200.