Drobo's used size is weird

I have a 2nd gen Drobo
Have opened Drobo Dashboard today, and it prompt me for firmware upgrade.
I did it.

However after reboot, I saw my Drobo asking me to add a new drive as my volume is almost full. However I remember I have only used less than half of my available space. (I have 3x1TB and I have < 1TB data)

My DroboDashBoard display the pie chart with 1.65TB used space. However the ‘table’ below the pie chart displays Used Space as only 847.80

I am using Mac, and used my Drobo as Time Machine backup.

What may cause the problem? Is it a bug of the firmware?..

How many volumes do you have?
Did you use disk utility to create any volumes?

What firmware are you on?
What dashboard are you on?

Only 1 Volume
I didn’t use disk utility to create volumes (and it works normal for months, if not years, before I upgrade the firmware)

Firmware: 1.3.5 [1.252.21110]
Dashboard ver: 1.3.1 [1.3.16839]

I would recommend running a repair disk from disk utility.

Have performed a repair disk.
I have even restarted my Drobo (put to standby mode and disconnect power, then connect power again)

My Drobo’s light and Drobo Dashboard’s pie chart still display almost fully used while I only used 4x%

Oh, just now, I discovered that, after quitting the Drobo Dashboard, Drobo’s lights become normal (showing around 40% used) after some time (around 1-2 minutes). Once I open Drobo Dashboard again, Drobo’s lights suddenly change to 95% full again.

Will it be a firmware bug? It is not only horrifying, but also makes me worried about what may happen if I put more data in it…

And you did not use disk utility to create the volume?

I would recommend either unisntalling and reinstalling dashboard following the proper procedure:

Or opening a support case. But the first thing we will tell you is to uninstall and reinstall dashboard.