Drobo 5N2 showing full capacity when it's not

I’m ready to burn this Drobo, that aside… here are my issues.

  1. My Drobo says it’s at 100% capacity which is odd, because it wasn’t previously and I didn’t add any files
  2. I tried deleting files, however there are folders that the Drobo won’t allow me to delete. I checked the drive and I have read/write access to everything. If I try to edit permissions, the drives unmount then remount moments later.
  3. I decided to add another drive and be done with the full capacity issue. The Drobo has all WD RED NAS drives since I’ve owned it. Slot 1: 4TB, Slot 2: 4TB, Slot 3: 4TB, Slot 4: 6 TB. After adding another 6TB drive to the Drobo to slot 5, the drive in slot 4 went red as a “failed drive”.
  4. I pulled out the slot 4 “failed” drive and reinstalled it. The data protection rebuild process started. I let it run overnight and it completed.
  5. After rebuild was complete slot 4 was now green and slot 1 was showing a failure. So I rebooted the unit and now slot 1 was green and slot 4 was showing a failure.
  6. I pulled out slot 4 drive and reinserted it and now the rebuild process is going again.

I’ve been playing email tag with Drobo support. They’ve asked me for times when I can support a remote login, which I provided but those dates came and went with no response. This whole process is infuriating. As soon as I can assure my data is safe, I’ll be switching it over to a Synology unit.

Can you share some screen-shots from the Drobo Dashboard of your Data Capacity (the pie chart) and the Volumes on your Drobo?

Hi, here are some screen shots of my dashboard. Note that before I added an additional 6 TB, the capacity showed 100% full then.

One last one please.
Please post the screenshot of the volume on your Drobofrom the top of your menu. It is a 1 liner.
My guess is that it says your volume is only 16TB.

You’re right. The total capacity is 24 but it only shows 16 total.

Ok. You Are experiencing Thin Provisioning. Here is a link that should help.

In you case you should have seen options from your Drobo to create another volume, but perhaps cancelled them? Alternatively, when you set up you Drobo you may have omitted selecting 64TB from the outset?

Obviously translate your array capacity for the one in the other thread.

EDIT: you should be able to set a single maximum 64TB volume on your Drobo after the factory reset.


First, thank you so much for your time in trying to help me. I really appreciate it. I’m really curious as to why my Drobo said it was full prior to inserting another 6 TB drive. I had been running been running 18TB of total storage for years with no issues of being “full”.

Second, I don’t have another location to transfer over all of my data in order to do a factory reset. I can’t tell how much data I have on my drobo but it’s probably 8-10 TB. I don’t have another hard drive that size so I can do a factory reset. :frowning:

Third, it doesn’t explain why drives will randomly show as “failed” but when you remove and reinstall them, they’re fine. :confused:


You probably have a good 12TB in this volume at the moment, and you will need to offload it to reset it.
Your second image shows the drives as green so it is accessible for the copy. There is no other way to do this.
The fails you have experienced are probably your disks partitions getting overloaded as your Drobo continually tries to move data around in a volume with little or no capacity. Remember that the Drobo has only initialised a fraction of the space on each Disk and that it the space where data is being read and written too, not the entire HDD.

EDIT: refer to the Drobo Capacity Calculator and load up a 5N2 with your HDDs to see how much capacity is used for data and how much is used for protection.

The drives show green in the one screen shot because they are flashing green/yellow since data protection rebuild is in process. I’ll have to see what surprise I get when it’s done. I’m guessing another random drive will show as “failed”.

Honestly, I’ve pretty much had it with this Drobo. For the years I’ve had it, it’s been full of quirks and issues. I’ll be replacing it with a Synology unit. I’ll copy the info off the drives onto that then just use it as a Time Machine backup until it dies, which is probably soon.

Again, thank you so much for your time and trying to help. I definitely appreciate it.

No problem.
From what you have provided, your Drobo is overloaded and trying to operate within the 16TB limit it has been set to. A reset to a larger volume size would make it far more effective and efficient.
It is more probable that your HDDs will fail before the unit does, so keep an eye on the warnings.