Replacing a disk on my Drobo 5N2

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Next time you might consider investing in enterprise class hard drives. I like the HGST Ultrastar line but really any enterprise class drive will give you a more reliable storage solution. You might also want to swap out the fan or add another one if you feel up to some hardware hacking. Heat is the big drive killer in those small enclosures.

I am sure that using better drives will get me longer periods between failures – but at these prices I find around $100 every 1.5-2 years does not dim my smile.

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I have had a Drobo 5N for a few years. When I had a drive fail it was a nightmare, but maybe I was just being overly cautious, or was using bad information from another user.

I was under the impression that after removing a drive, you were REQUIRED to wait for it to ‘settle up’ on fewer drives before tossing in a new one. Can you literally just pull out the failed drive, slide in a new one, and be on your way (while it does its housekeeping on the new drive in the background)?

Does it go the same if I pull out a small drive to replace with a larger? This would be a ‘game changer’ as it were.

Yes. The steps AFAIK:

Remove face plate.
Press Eject button on indicated bad disk
Remove indicated bad disk
Insert new disk of any size
Replace face plate.

Yes. I believe you can go down or up, Drobo recalculates. I’ve never gone down in size as disk prices always seem to go down.


Mine is updating firmware while still integrating the replaced disk – unless the integration was that quick. Gen 1 Drobo took days to bring a replacement disk up to speed. This one seems to be Johnny on the spot.


One of the things on my list when I’m employed again is to get a Drobo and consolidate all my external storage as well as redirect all Time Machine backups.


Yeah, I had five 3-TB drives in my Drobo 5N that got moved to the 5N2, but only had failures in the 5N. I would take out the drive, wait for it to finish rebuilding its database (as stated, it could be 24-36 hours) and then put in the new drive. I never put in a larger one due to this perceived wait time. Now I will feel less reluctant to get a bugger drive if I see them on sale and use it.

What are you using for online backup?

Are you just duping your files across drives or is your data still in tact because of a RAID config? (I’ve never understood which RAID to use).

Drobo uses a proprietary RAID-like disk distribution and recovery algorithm that purportedly ensures up to two disks can fail at once and you’ll still have access to the filesystem. Rebuild speed varies by device. I was watching movies at 1080p with one disk failed all weekend.

I feel you. They can be pricy. The 4TB HSGT HUS724040ALE640 runs about $130 right now so the low end of enterprise class can be had for not much more than the desktop version. When it comes to my data, I’m a belt, suspenders, and duct tape kind of guy. I like RAID 10 arrays with local and offsite backups.


Interesting. Thanks!

Of course, if your house gets smashed by an earthquake then all bets are off. Ideal is to have off-site redundancy, though my usual recommendation (crashplan) is getting out of the home backup business. I suppose one of the services in the BB Store might be worth a look.

Out of curiosity, have you tried any of the other (non-Drobo) RAID NAS devices? Many of them are quite a lot cheaper than the Drobo. I’m currently using a single-drive NAS, but have been considering moving to a RAID system.

I preach RAID 1: one disk will rebuild everything, and there is nothing fancy about that one disk – give me a reasonably stock Linux system and I can recover the data. If the power supply were to die in an old NAS unit running RAID 5, or 6, or maybe even 10, recovery could mean trying to scrounge the same model (down to the same firmware, potentially). That could be a very tall order.

With RAID 1 (and hot swap), I can just grab one disk from my running system while sprinting out the door. This actually served me well during several wildfire evacuations, and when worse actually did come to worst, data recovery was the least of my problems.

Are the new Drobos quieter than the Mark 1 and 2 models (with 4 disks)?

I have one of the Mark 2s still going strong, I love it, but oh god the fan noise is ridiculous. For the money they charge they could have put a quieter cooling system in the box.

It depends on the size, heterogeneity and reliability of your drives.

To give an example of why this matters: let’s suppose you buy a case of business desktop grade, one terabyte hard drives and use RAID5. The drives, being bought as a set, are not unlikely to be from the same production batch, and have very similar working lifetimes. So, RAID5 lets you rebuild a failed disk drive’s data, but it takes a long time, since you have to calculate the missing data from the remaining data and a check code. It will take longer if you are doing other stuff (reading and writing data) at the same time. The odds of another drive failing before the rebuild is done are higher if your disk size is bigger because the time is longer, if that makes any grammatical sense, so with these slow, large desktop type drives RAID5 is a bad choice.

Personally, I use RAID 1+0 in my home server arrays. That is, I distribute my data over sets of mirrored pairs. I also generally have a spare drive in the array that will automatically replace a failed drive. I routinely run my arrays (which are made from hardware I scavenge from old PCs and servers found in dumpsters) for 10 to 15 years around the clock with zero hardware* maintenance. They get full of spiders and airborne gunk but keep on ticking.

* I do keep my software updated.

Which tools did you use to open the box the replacement HD came in?

Opinel #8 picnic knife.

Good choice.
I was hoping for something more spectacular, though.