2.6.x scsi software raid IO tuning
I receintly came across several SCSI racks with drives. So I've been playing with various software RAID setups with between 8 - 15 drives. I have a sym8xx SE chain and a AIC7xxx HVD chain. Using Bonnie++ to measure IO throughput of my RAID 5 setup.
I also decided to try the latest 2.6 test kernels. I built the 2.6 with the same setup as my 2.4.22 kernel. Preemption was disabled and I believe that I have all debugging output turned off.
I found that in every test case I ran Bonnie++ reported the 2.6 kernel IO as 3 to 5 MB/s slower than the 2.4 kernel. File creation/deletion was also slower.
Is there some tuning knobs that I need to tweak or some option that might be enabled causing this? I thought the 2.6 was supposed to have much better IO throughput when setup in non-preempt. So I expected to at least get the same numbers not less.
My apologies if this is a md issue rather than a scsi issue but out of my info searches so far this list seemed like the best place to ask for info.
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Richard A. Smith [email protected]