I have a Drobo S (gen2) that I bought new in 2011. It’s been running strong since I bought it, except for the fan. So, we’re at more than five years now.
About a year and a half ago (Spring 2015-ish), I replaced the fan inside of it, because it would make such horrible noise. At first, I thought the device was failing, or I had a bad drive getting ready to fail, but every diagnostic I could run found no problems. I eventually narrowed the noise down to the fan, and confirmed it when I had a fan go out on a desktop computer in my house, which started making the same noise. I decided “what the hell, its out of warranty anyway” and opened it up. I had to build a new cable for the fan power since it didn’t use a standard fan connector, even though it uses a standard 120mm fan. Since then, it’s been back to being quiet, and handles my data just fine.
I originally ran the thing on USB 2.0, until I upgraded my computer for USB 3.0 support. I tried it on eSATA for a while, but found it to be unstable. I don’t know if the problem was Windows 7 or the Drobo itself, but I was constantly losing the array and having to reboot to get it back.
I started running the thing with two 3TB Western Digital green drives, eventually adding three more, also Western Digital greens. I later replaced two of the 3TB drives with two 4TB Seagate 7200rpm enterprise drives. I didn’t do the normal ‘replace a drive and wait for it to rebuild’ scenario. I needed to reformat the thing from NTFS to HFS+ since I had migrated pretty much my entire life from Windows to Mac at the same time. I copied all my data out (9TB of data) to a temporary disk array, reformatted the Drobo for HFS+, then migrated all my data back. It took about 9 days total, 15 days if you count the days wasted while figuring out that the Paragon NTFS driver for Mac craps out after 2TB of sustained data throughput.
Since migrating to Mac, I’ve been running it on FireWire 800, which I have found to provide better sustained speeds than the USB 3.0, even for it supposedly being only 1/5th the speed of USB 3.0. The USB 3.0 had great burst speeds, but horrible sustained speeds if I was doing a large data transfer. Whether the fault was with my USB 3.0 controller or the Drobo, I don’t know. But I do know that it has been just as rock solid on the FireWire 800 as it was on the USB 2.0 and 3.0.
(The reason for moving to FireWire after moving to a Mac in 2015 was because I moved to a 2009/2010 classic Mac Pro, not a modern Mac. I have done some custom hardware and firmware upgrades to it, though, so it performs just like modern Macs, sometimes even better. But due to limitations to the chipset, it just won’t support USB 3.0 without a PCI expansion card, which I have yet to install due to technical reasons. So, I stick with the FireWire 800, which is twice as fast as the USB 2.0.)
I use my Drobo for storage of backup data, movies, music, and photos, so it gets daily use, both reads and writes. I hold about 9.5TB of data on it right now, without dual disk redundancy, since I have yet to have a drive fail in it. I’m sure my paranoia will get me to enable dual disk redundancy if I ever have a drive fail in it.
In short, the Drobo S has been rock solid for me, and I would recommend it as a great used device. When I eventually buy a new Mac with Thunderbolt support, I’ll probably buy a new Drobo as well. But I’m probably a couple years away from that, still. I’ve explored building a FreeNAS box for replacement, mostly to use ZFS since it has great protection against bit rot, but so far, my experience with my Drobo keeps me looking at a new Drobo for eventual replacement. By the time I do get around to replacing it, I’ll have to evaluate whether holding onto an HFS+ device is worth it after Apple migrates everything to APFS. I can only hope Drobo will upgrade the firmware for their products, including legacy products like the Drobo S, to support APFS. Otherwise, I’ll probably be back to looking at a ZFS-based FreeNAS box.