This is mostly an IOPS dependent answer. Do you have multiple hot services constantly hitting the disk? If so, it can be advantageous to split the heavy hitters across different disk controllers, so in high redundancy situations that means different dedicated pools. If it’s a bunch of services just reading, filesystems like ZFS use caching to almost completely eliminate disk thrashing.
This is mostly an IOPS dependent answer. Do you have multiple hot services constantly hitting the disk? If so, it can be advantageous to split the heavy hitters across different disk controllers, so in high redundancy situations that means different dedicated pools. If it’s a bunch of services just reading, filesystems like ZFS use caching to almost completely eliminate disk thrashing.