Higher capacity drives

Will Drobo be qualifying higher capacity drives anytime soon?

I’ve noticed that Toshiba has some pretty cheap 16 TB and 18 TB drives, but I couldn’t buy them because Drobo has only tested drives up to 14 TB.

Will Drobo be testing some of these higher capacity drives in the near future? It really doesn’t make sense to be buying 14 TB drives if 16 or 18 TB drives will work because the highest capacity drive will be used for parity, and replacing a 10 TB with another (say 18 TB) would be pure gravy and yield an 8 TB storage bump.

Assuming a 5 bay unit on single redundancy filling it with anything bigger than 16TB drives would put it over the 64TB maximum supported total storage capacity.
Maximum Volume Size and Largest Size Drive (drobo.com)
I’d imagine 16TB would work without issues on the basis you’re still within the stated supported max storage, I don’t think I’d risk anything bigger.
18TB drives may or may not need either a firmware update, or a new product line to be supported.
I wouldn’t risk it without confirmation from Drobo themselves.

Then again if maximum total storage capacity refers to what’s inserted rather than reported & is binary 64TiB because of some architecture limitation, then 14s would actually be about the limit.

Update: That last got me thinking & remembering something I read…
Drobo 5N; Drobo 5D: 64TB Volume Support
Reading between the lines of that I won’t be expecting to see 5N units supporting anything bigger than what’s currently tested, because it needs to be able to address the entire storage to do the “Beyond RAID” thing behind the scenes. What processor the other units use isn’t stated, any with a 64 bit one may see bigger drives qualified.

Here is a thread on this issue following a discussion I had with Drobo support some time back. He noted that the 64TB volume in a Drobo would equate to 4 x 16TB Drives + 1 x 16TB Drive for redundancy. 16TB drives have been used by others on this board without issue.


Yeah, I’ve already gone through the calculus of capacity expansion, and went with migration to an 8D - later, when software was updated for it, I reformatted and increased capacity to 128 TB (which was painful - I wish there was a software way to upgrade).

Total dataset size and individual drive size are totally unrelated. One is maximum capacity of the RAID array - the other just what the hardware/firmware can address in a drive slot.

My 8D currently has 14x4, 10x3, and 4x1 - remember in any array you have at least one invisible drive (parity) which doesn’t contribute to capacity. Given cheap enough high capacity drives, I would like - if I could get it without reformatting - an active spare. When you add a drive it would be nice if you were presented with an option to make it an additional data drive or an active spare.

As always, bigger drives have a higher and more cost effective impact than anything else - replacing the 4 TB with an 18 TB would replace one of the 14s as the parity drive and leave 4 TB idle, but add that 14 TB to the data pool yielding a 10 TB expansion. You wouldn’t see the full benefit until additional 18s were added.

Nearest you get to a spare is dual redundancy, that can be activated without a reformat. I’d also highly recommend it with big drives, last thing you want is an unrecoverable read error during a rebuild, & the chances are high enough to be a significant risk with single parity, especially with consumer class SATA drives. I won’t run anything bigger than 4TB drives without enabling it.

By all means drop support a line for confirmation, (or sales, but sales will likely refer it to support) but I suspect you’ll be fine with those big drives in an 8D.


How do you active dual redundancy (replacing a data drive)?

I’ve asked Drobo about larger drives in the past, when I was still in support (support for my 5N2 ran out in November 2021). They basically told me that larger drives have not been tested by them but should work just fine. Based on that response, I replaced 2 8TB drives in my 5N2 with 16TB drives. It’s been working quite well for the past several months.

Even my ancient Drobo FS took 10TB drives (the stated maximum was 4TB) just fine, until I retired it in 2020.



Provided you have sufficient space (I don’t), you can activate Dual Disk Redundancy directly from the Dashboard:

Drobo Settings > General Settings



How do you active dual redundancy (replacing a data drive)?

It’s literally a checkbox in dashboard followed by a long wait while it does a data re-layout.

Well, I replaced the 4 TB drive in bay 6 with an 18 TB; after a few moments of terror the 18 TB drive was recognized, and I proceeded to flip on dual redundancy and after generating about a quart of stomach acid the Drobo announced it was converting to dual redundancy.

So … after another 81 hours or so of relayout I should have a 65 TB data set :face_exhaling:.

Just a word of warning: Dual redundancy does not protect you against your Drobo unit failing. Such an event would be a single point of failure unless you have another Drobo you can switch your array to, or you can purchase a replacement Drobo unit quickly.

I strongly recommend an external backup of your data with a regular protocol to ensure the data is up-to-date and healthy. Another tip: if your budget allows - choose enterprise HDDs over consumer HDDs as this also lowers the likelihood of HDD failure in a home or SME installation.

Whilst I fully respect the call for dual redundancy, in my case I was comfortable to revert back to single redundancy after I had built up an external backup set, as this became my data protection bank (in effect my dual redundancy) whenever I was upsizing HDDs in my Drobo - as I knew I could rebuild the array with the backup data back in my Drobo - or even another manufacturer’s RAID unit - if something went horribly wrong. Unsurprisingly, my external data backup is made up of ex-Drobo HDDs after upsizing.

I primarily use my Drobo for fast bulk storage (it’s an 8D) and it’s backed up to a Synology 1817+ NAS in another room (on another floor).

For backups I go to a local USB attached HDD clone drive (a Thunderbolt attached HDD for my primary) along with a minimum of two Time Machines, of which one exists on the NAS array. My primary computer also has a cloud backup on BackBlaze along a complete backup of the Drobo 8D.

The only important data exists on my primary computer.