Build my own DAS


Build a Thunderbolt 3 / USB-C direct attached storage which supports both M.2 NVMe SSD (x2) via PCIe and spinning HDDs (no more than x6) via SATA interface. I prefer for this to be rack mounted since I already have a server rack if it’s too loud but a small standalone PC case is also fine.

As per my understanding this probably just needs a host thunderbolt / usb-c interface with PCIe card and SATA connectors. And of course a proper case with enough space to mount all the drives and

There are many NAS build guides out there but unfortunately very little information available for building a DAS.


I will connect this DAS to a Mac Mini. Will be using the macOS Disk Utility to setup the two NVMe SSDs in RAID 0 where I will have some faster read access data like Apple Caching Server data for example.

And have a backup software which will copy some of the other data from SSDs to HDDs which will be configured in RAID 1. Other copy of backup will happen in cloud as well.

My Background

Computer Science engineer. Will be mainly using this storage as my personal cloud backup and for my media library.

I have built gaming PC’s before but never build a DAS. I guess this needs some kind of USB-C host interface without any CPU or RAM maybe.

Example products

Example products that I have looked at are:

  • OWC Flex 1U4 - a rack mount usb-c DAS which has 4 bays for HDD / SDD or even M.2 drive using their own shuttle one (U.2 bay). It also has one empty PCIe slot which I can use to mount a dual m.2 drive pice card

  • Promise Pegasus R12 - this is a newly launched product which also supports automatic M.2 NVMe ssd caching using it’s own software PromiseRAID.

I would like to build something similar if at it's possible and worth doing a custom build as oppose to some of those consumer products which tend t be expensive!.

Thank you in advance!

There aren’t really options to DIY Thunderbolt storage. The Mac Mini’s interfaces are going to be a point of difficulty for connecting lots of high speed storage. The products you linked are expensive because Thunderbolt devices are relatively uncommon and do just cost more.

Wanting a personal cloud sounds like building an actual server instead of a DAS. As for connections, luckily personal cloud and media library likely do not need any more speed than standard 1Gbit networking.

You’d want to either connect with gigabit ethernet or individual drives by USB-C or Thunderbolt. If you’re hell bent on high speed I guess you can get 10Gbit ethernet adapters to Thunderbolt but they’re largely cost prohibitive themselves.

An alternative is something like the TR-004 from QNAP.

Thank you for your response on this!. I don’t want to build a separate server because I have mac mini for all my computing needs as a home server.

How about options for a DIY USB-C storage with m.2 nvme and hdd options?. Is there not way to build my own USB-C host direct attached storage or are we saying the price point would be similar to just buy one of the pre-made consumer products?.

You’re not going to be assembling your own multi drive USB-C storage device. Not in any way I have ever heard of. You can go as nuts as you want adding individual drives and even USB-C hubs now but it’s a mess.

Once you want to start managing large amounts of storage, and your only computer is a Mac Mini, it’s fine to not want a server, but generally speaking, you now need one - to manage the storage.