Drobo 5c insatiable appetite for HDDs

I have had this Drobo 5c (bough tin HK as I used to live there) since 2018. I bought it because I read that “basically throw in any drives you have and the system assembles them into a RAID”.

I had 1 4TB WD RED and 4 3TB PURPLE drives lying around. So that’s what I put into it. Almost immediately it started showing some of the drives as “warning” and didn’t even recognize the others.

This couldn’t be blamed on the drives as they were testing fine. So I persisted and kept putting them back in. The Drobo would rebuild itself overnight and usually I’d find its ok for a few days till the next one tripped over.

Finally, for about 2-3 months the unit worked as expected. All drives were showing normal and performance was decent 50-100MBPS read/write.

Then I moved to Austin and the problems started again. First one then several drives failed. Again testing each drive individually out of the Drobo (using a caddy) showed no problems (worst case it would be 99% health with a few weak sectors).

Finally decided to head over to the Drobo site to see if I could find anything. Figured that maybe it was because these were surveillance/NAS drives so they were not great for the Drobo. In fact the RED is not recommended for use. [Side rant: WHY THE HELL NOT?]

Plus the disk read write speeds were also slow during the few times that the system was working without errors. So this week I decided to buy 5 new BarraCudas because I thought they were recommended (not realizing the difference between Pro and the regular ones).

So I got 5 new 2TBs Barracuda and changed them two at a time with the old drives. Took almost two whole days but the process finally ended this morning.

I found that the IOPS were still pretty high >250 even after the Drobo declared itself to be fully functional but figured that it was just some background stuff going on so I didn’t start any real disk activity.

Suddenly - just when I thought I had emerged out of DAS/RAID hell - it starts showing one of the new drives had an error (it showed it first as completely missing and then back in the slot but with a “warning”).

I just took out the drive and tested it with Seagate tools. NOTHING is wrong.

Even worse, a few hours later ANOTHER one starts showing a warning.

I’m going crazy here. SO I tweeted @drobo. After describing the problem all they could do was say:

"The BarraCuda drives are not supported in the Drobo because they are not RAID optimized. The BarraCuda Pro drives will provide maximum performance and are compatible. Apologies for any confusion on this! We recommend contacting our support team if you experience further issues. If you have any questions, please let us know! "

  1. I don’t know what the hell is the meaning of RAID optimized? How does one even know whether a drive is RAID optimized or not?
  2. The 5c row on the “Choose Drive” page says it takes Desktop SATA drives. I am using desktop SATAs
  3. I understand if different types of drives give differing performance. I don’t understand why the Drobo shows them as “failed” even though they are just FINE.
  4. Even if I were to return the regular Barracudas and get Barracuda Pros, how do I know the unit won’t eat through those? What guarantee do I have that spending more than 2x of what I just did will get me the result I want?

Hi, I’m not sure about the 5C but I am sure about Seagate IMO. Don’t even. I’ve been doing this for well on 2 decades (going on 3) and I’m an ardent NOT fan of anything Seagate and I have a pile of dead ones to prove it. Yes, they’re a few dollars cheaper but they just don’t hold up under any circumstance. I actually tried them in my first gen Drobos (USB 2 so talk about slow, ack…) and I got 6 - 9 months MTBF before I went with Hitachi (now WD). Those Hitachi drives were still working until the Drobos died (dead fans and power supplies) 10 years later. I’ll bet if I plugged the Hitachi drives back in they would continue to perform (they’re just too small).
“Raid optimized” means several things but the biggie is vibration tolerance. All drive arrays vibrate so drive modules have to have firmware/hardware that can tolerate this problem. Seagate doesn’t so your phantom “fails” are usually because of this. That’s why when you take out the drive and test it individually it looks happy (no chassis vibration) but try to run it in the Drobo?. Yes, the Drobo chassis shakes badly but you get what you pay for. My 5Ds all have vibration issues but my drives stay happy. I’ve been running Hitachi’s Deskstars Ultrastars, WD Reds and Toshiba for multiple years now w/o too many failures. over 100 drives in 12 5Ds (they get swapped out as I get bigger drives) and maybe 3 drive failures (2 WD and one Hitachi) since I stopped using Seagate. Oh by the way ALL of the Seagates (9) have done a hard fail (No spin, loss tracks and blown circuitry) so I would stay away (even the Pro). Someone should do a survey of all the data centers in the world and look at their current piles of dead drives. I’ll bet anything Seagate will have the biggest piles.

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