I'm quite confused based on my own tests and some of the information provided about controllers in this forum.
I started my home server running ZFS with drives connected directly to the motherboard. The performance was fantastic. Then I wanted to expand my array but ran out of SATA interfaces, so I got a H200 controller and flashed it to IT mode. The performance was absolutely horrible, the server IO-Wait jumped through the roof. Then I learned this is because the HBA controller disables cache of the drives, ok that's fine so now I need a controller with cache. After additional research, I'm reading that the cache won't work on controller cards flashed in IT mode. So what is the point of getting one with cache mode when relying on something like ZFS vs hardware raid? How does one get an expansion card, use ZFS and allow cache to continue to work. The server has a UPS so power failure is not an issue. Any suggestions are greatly appreciated!
I started my home server running ZFS with drives connected directly to the motherboard. The performance was fantastic. Then I wanted to expand my array but ran out of SATA interfaces, so I got a H200 controller and flashed it to IT mode. The performance was absolutely horrible, the server IO-Wait jumped through the roof. Then I learned this is because the HBA controller disables cache of the drives, ok that's fine so now I need a controller with cache. After additional research, I'm reading that the cache won't work on controller cards flashed in IT mode. So what is the point of getting one with cache mode when relying on something like ZFS vs hardware raid? How does one get an expansion card, use ZFS and allow cache to continue to work. The server has a UPS so power failure is not an issue. Any suggestions are greatly appreciated!