ZFS on Hardware RAID

[Borja Marcos]

> On 22 Jan 2019, at 12:52, Borja Marcos <borjam at sarenet.es> wrote:
> 
> HBA mode: when the card is in IT mode *or* it does expose the actual targets to the CAM layer. In the past I did it
> by manually patching the drivers and I’ve kept systems running smoothly for many years despite using IR cards. 
> Currently you can use hw.mfi.allow_cam_disk_passthrough tunable to achieve the same effect without ugly tinkering. 

This is what I did long ago to have IR cards expose the targets to the CAM layer. It was a suggestion from
Scott Long. I first did it with AAC cards, later with MFI ones. 

https://lists.freebsd.org/pipermail/freebsd-scsi/2007-October/003223.html

Some years ago the “recipe” was made official (although not encouraged) by adding the 
hw.mfi.allow_cam_disk_passthrough tunable.

Doing this I didn’t need to create volumes or anything. Just plug the disks and avoid to configure
anything for them on the RAID controller. The disks appeared as “da” devices and I could
hot plug them and use the CAM commands without any issues. 





Borja.