Quote:

My question is:
Even if two separate arrays (RAID 1) are on the same controller on the same channel, doesn't performance improve if one array is doing mostly write operations and the other doing mostly read operations?



I'm not sure you've framed your question fully.

When you say "improve" what is is that you are comparing it against? What is the less efficient option that you are thinking of?

Your constraints will be the amount of disk cache memory on the disks and controller card, how it is used and how quickly disk blocks are written (and read). It is unlikely that your controller itself will be an IO bottle-neck unless you have a lot of spindles in which case I guess SCSI arbitration will begin to have an impact.