1U solutions for expanding storage

Hey All,

Surprise surprise, my 48TB array that should never run out of storage has run out of storage.

Because I'm running a ZFS array on TrueNAS Core, theres no real easy way for me to upgrade the hard disks themselves, so I'm looking to create a second pool.

Unfortunately, I only have 1U of space remaining in my rack (which is a half size network utility cabinet) and so my options seem pretty limited.

I think what I would ideally need is:

• 1 U, Half rack size
• At least 4 3.5" bays
• SAS connected (this is how my current drives are connected and throwing another external SAS controller in my NAS would be the easiest way (I think) to add this capacity)

The only solution I've been able to find that satisfies these requirements is this device from iStarUSA but I can't find it for sale anywhere

I've also seen some QNAP (TR-004U), Synology (RX418) and ReadyNAS (RR2304), but they seem custom built to work with their proprietary NAS systems and it is unclear if I can use them with my home built TrueNAS Core solution.

Does anyone have any suggestions for products that might meet my needs?