Time Machine not backing up Drobo

[BobShaw]

Hi,
I have a Mac mini server running 10.9.5 and my data is on a firewire connected Drobo S.
The server backups every night at 1AM using Time Machine. There are multiple backup disks, including a Drobo 5N NAS and a directly USB connected 3TB drive.
This used to work great.
I had two partitions on the Drobo S. One limited to 3TB as I knew Time Machine needed to know the size of the drive. The other was a spare partition to use up the rest of the advertised space.
Unfortunately I read somewhere that Drobo does not support multiple partitions, so I backed it up and reformatted it to a single partition using the Drobo Dashboard.

Unfortunately backups haven't worked since. The drive is not excluded. Time Machine knows it's there because it creates a folder in the back up for it, but the folder is always empty after the back up completes. The other drives back up fine.
If I run a Backup Now the same thing happens.
Any ideas how to resolve this please?

[BobShaw]

Well to answer my own question, there is no answer.

I have copied the contents of the Drobo to another drive, reformatted the Drobo using Disk Utility to a single partition limited to 3TB. Then copied the contents back. Some files failed to copy so perhaps corrupt, but they copied fine from another backup drive, so probably bad sectors.

Put it all back together and now it is backing up with Time Machine.

I have two Drobos and won't be buying any more.

[digitaldog]

I have two Drobos and won't be buying any more.

Never had one but based on user experiences I‘ve read about over the years, your decision is a sound one.

[CoyoteButtes]

My experience with Drobo is that their most consistent and reliable function is to serve as a paperweight. I've had consistent trouble with them, and most recently the company would not honor a warranty on a unit less than a year old. I will never spend another dime on Drobo.

[John Sluder]

I "believe" the issue is the size of the Drobo, as you stated once you had changed the 3TB partition and used the full Drobo size the Time Machine failed. The Time machine saw more Drobo Volume that it could back up.

One of the issues is that the Drobo can not dynamically expand the Disk Size as you add bigger disk, I have mine set to 16TB but I only have 8TB (2TB X 4, of 5.42TB usable) of actual disks, the finder show 16TB, is false.