Drobo

Am I right in thinking....

If I use my DroboPro iSCSI for ESX - the maximum vDisk I can create for a VM is going to be 2TB - so any Windows VM’s will only be able to see a 2TB max disk?

There is no way of creating a bigger disk for my Windows VM if I use iSCSI with ESX.

I guess the answer would be, Drobo Elite…?[hr]
Or can I pass through a 16TB LUN directly to the VM - looks like I can. This is probably basics, but I’ve not done it like this before. I’ll test and be back soon!

VMWare VMFS supports a maximum LUN size of 2TB.

RDM (Raw Device Mapping) supports more than 2TB in ESX 3.5, but not in vSphere (which is what I’m using). I was attempting to Extent the ESX datastore to 16TB (the limit is 64TB) but I still get the error associated with the 2TB limitation. Extenting the Datastore was the way to do this in 3.5.

Essentially, the RDM LUN size ability to be more than 2TB was a ‘bug’ and was fixed in vSphere.

The single host restriction of the Pro is a huge shame. My scenario is as follows:

I have a 16TB LUN provisioned and with a heap of stuff stored on it. I want to be able to grow to 16TB, so don’t want to sacrifice it.

I have limited storage in my ESX server and need to store a heap of VM’s. So I would like to be able to connect to the Drobo from ESX using iSCSI but still be able to present my 16TB LUN to my 2008R2 VM. It can’t be done, basically.

If I could present my iSCSI to more than 1 host - hey presto.

My only options (other than buying an Elite) are to break up that 16TB LUN in to 2TB LUN’s. Doing so would mean I would eventually have to split my data or use RAID in Windows - far from ideal. I guess the other option is ESXi rather than vSphere - but then I’ll be using an unsupported hypervisor.

What happens if you install the Elite firmware on a Pro?! :stuck_out_tongue:

You can’t install Elite firmware on a Pro.

Well no, but I’m sure the code of the Pro firmware could be changed to enable multi-host…

The pro was not designed for multi-hosting. It can cause data corruption if more than one host is accessing the same LUN at the same time.

In fact, I can’t even go with 2TB LUNs anyway as I would have no way of copying the data from my existing 16TB LUN. I.e. I can only access the 16TB LUN from Windows and could only add the 2TB LUN too windows, if I attached the Drobo to ESX (which would then take the 16TB LUN away from Windows).

So, I am stuffed.