replaced drive in FS dashboard does not see it

Hi I have a FS with 5 2TB drives in it. I was running low on space and the orange warning sign came up on my desktop. I replaced a 2TB drive with a 4TB drive and the Dashboard is reporting 7.24TB total space. So, it’s like the 4TB drive isn’t there. Does Drobe need to format the new drive before using it? Thanks, mike


Thats perfect normal and working exactly as designed.

You need to upgrade TWO drives before you start seeing any additional a space available.

Think of it as… the first 2TB of your new drive is mirrored/protected by the other 2Tb drives already in your drobo, the next 2Tb of your new drive… has no where to be mirrored onto, so it cant be used as yet. if you view the capacity… you should even see the additional 2tb as “reserved for expansion”

try the capacity calculator and you will see:

The other way to think of it:

Total space available = Total of all drives MINUS the largest disk

if you only have one big disk, that sum always works out to be the same result. if you replaced your 4Tb disk with a 20Tb disk, you’d still only have 7.24Tb until you replace a second drive.

after that, everytime you put in a bigger disk, you will be getting more space