are you using RAID with TrueNAS? this is a
Very Bad Idea (TM) to begin with. if you want to use hardware accelerated RAID, you should not be using zfs, and TrueNAS. if so, these are not the forums for you.
list out your full hardware and your pool layout.
one of the problems with raid cards is that you typically need the same raid card family to access the disks, as they add proprietary gunk to the disks. they also obfuscate the storage and can cause massive issues and data loss with zfs, which relies on accurate and direct access to the disks.
a google search on "SAS 6IR" seems to indicate this is a very old sas1 RAID only controller, so yes, you need a compatible raid controller to access the disks. if you can find a pcie card that is the same controller that will work. some googling seems to indicate that this might be a pcie card, with a standrd pCIe connector. if so, you should be able to fire it up with any motherboard to get access to the RAID, enough to rescue the data from it
assuming you don't have backups (RAID is not a backup), based on what I see here, you need to get one system to read the RAID, and then
a) make a backup (temp location), destroy the raid, put the disks in the new system with supported TrueNAS config, and copy it there.
b) make a new pool on supported config and copy the data there
neither of these is a really easy process.
