Good rack mounted DAS solution that I came across for my homelab setup (M1 Mac mini, Plex + Time Machine + File Storage). Fit nicely in my rack and was able to get it setup in about an hour. One small glitch I hit was that the Raid Manager software didn't recognize the DAS until I installed my HDDs into the unit. I am using 2x Seagate X20 18 TB HDDs in a RAID 1 configuration, and 2x 5 TB WD in another RAID 1 configuration. Am able to get sustained Reads of ~225 MBs and Writes of about ~240 MBs (tested using Black Magic Disk Speed Test). I tried switching the unit to RAID 0 for the 18 TB drives, but didn't see any performance improvement (which for my homelab is fine). The Software configured RAID is nice since I don't have to fool around with DIP switches. And the SMART status for each drive is displayed nicely in the RAID Manager Software (although I can't seem to find a way to have it email / push notification for a failed SMART indicator on a drive). One caveat, this unit (and the TR-004 non rack mount) is limited to SATA II (although compatible with SATA III drives). For my spinning HDDs this wasn't an issue, but could bottleneck for SSDs. I will note the TR-002 (2 bay non rack mount variant) can run at full SATA III speeds which is odd. Confirmed this with QNAP tech support. Overall I recommend, but dropped 1 star for the SATA II limitation. ---- Update ----- After using this for a few days, I ran some more speed tests on the device and have to say I'm pretty disappointed. I tested with an SSD in one of the bays and my 2x 18 TBs in the others. I turned off all raid modes and just accessed the disks directly, and was shocked at how poor the r/w speeds were. When running the Black Magic Disk speed tester, I started testing 1 of the hard drives to get a baseline performance (around ~225 MB/s read speed) and tested writing to the other HDD by copying a large file (just used macOS to generate a large random file of text ~ 10 GB in size). As soon as I started copying the file, the read speed tanked down to ~25-30 MB/s! Writing speeds were about the same (tried both copying to/from the drive and 25-30 is the most I could get while both black magic and the copy operation were running concurrently). Just to be sure this wasn't the HDDs, I popped an SSD I had into the unit to test with (again no RAID mode, just direct disk access). The SSD had slightly better performance, maybe around ~50 MB/s (while copying files to one of the HDDs), so that led me to believe it might be a limitation of the backplane in the unit. Just for kicks, I took 1 HDD and the SSD and put it into another 2 bay USB-C caddy I had lying around. With the same Black Magic software, the HDD was able to sustain Read / Write speeds of ~300 MB/s, and when copying files to the SSD only dropped down to about ~260 MB/s (the SSD speeds were closer to ~500 MB/s). So I am concluding it has something to do with this device and returning / no longer able to recommending the unit. Updating to 1 star.