Drobo

Infinite re-layout

Does anyone at Drobo support know what they are doing?

So my drobo has been working fine for about 18 months, i’ve upgraded drives, it has successfully re-laid out data.

A week ago it told me to upgrade the drive in slot 4 (drive setup was 1TB WD Green drives in slots 1-3 and a 320GB Seagate in Drive 4) as it was filling up. I popped out the 320GB and put in a 500GB in its place (not much bigger but all I had)

It started its re-layout and after 24 hours had not finished successfully. The Drobo was no longer recognised in OS X (the disk you inserted was not readable by this computer) and drobo dashboard could see the drobo, showed how much was used and how much was free (75% and 25% respectively) but the volume was now called “Unformatted”. and at this point it would go into “Data protection in progress” (4 lights flashing green and orange) for a few hours then back to “Drobo cannot protect your data” (bays 1-3 Green, Bay 4 Red) for 20 minutes, and this would keep cycling.

After a day of this, it then remained in relayout mode (4 flashing lights) permanently, and would spontaneously reboot whilst doing so.

I opened a ticket with diagnostic log at the start of the week, first the technician told me that one of the 1TB drives (Bay 3) had 3 full timeouts and advised me to wait till its in the “Drobo cannot protect your data” and then remove the 1TB drive and replace it. When I explained that its stuck in a relayout so pulling out that drive would mean data loss, he asked for my power supply part number and then handed me over to tier 3.

Tier 3 told me to take the 1TB drive in Bay 3 and clone it onto another 1TB drive. I didnt know how this could be done (as I know the drobo has its own file system and the drive wouldnt just show up in Mac OS X) so I asked them what software to use, they advised Carbon Copy Cloner.

I received the replacement 1TB drive and sure enough Mac OS X and Carbon copy cloner cannot see the Drobo disk. And if I initialise it I will lose the data on there.

And of course no weekend support so I just have to sit here till Monday…

There is software available which can clone a disk. it doenst matter what the file system is or whether your OS can see it or not - it simply copies EVERYTHING from one disk to another, so therefore it doenst matter whether your oS can understand what is being copied… this is what support was advising you to do.

i believe carbon copy can do this - its a block level copy (i’ve just glanced at their website) , but i dont have a mac so cant really advise you further

Carbon copy requires its source and target drives to be HFS+ with a GUID Partition table or Apple Partition Map, which the drive from the drobo pack doesnt have.

yeah i found that in the FAQ

ok well basically you need a utility which can clone a disk - and by clone, it means that it doenst care what the Filesystem on the disk is - it just need to make an exact replica, you should have several choices of software to use, but since im a pc guy, i cant really advise :frowning:

OS X has the command-line utility dd built in.

First connect your source disk to your Mac then open up Disk Utility and select the Disk. Click on the info button and note down the value of the Disk Identifier field. It will probably be something like “disk1”

Then connect your destination disk to your Mac and do the same thing in disk utility. It will probably be something like “disk2”

Now as an admin user in OS X open up a terminal. You can use the dd utility to clone from one disk to another.

sudo dd if=/dev/source-disk of=/dev/destination-disk bs=4k conv=noerror,sync
For example:
sudo dd if=/dev/disk1 of=/dev/disk2 bs=4k conv=noerror,sync

The “noerror” directive says not to stop if it hits an error such as a bad block. The sync option says to pad to destination with zeros if it hits a bad block in the source.

The bs=4k sets block size - how big a chunk it will copy at a time. Larger bs will make it go faster, but if it hits a read error then that whole chunk will be written as zeroes in the destination. 4k is a reasonable compromise between accuracy and speed. If you want it as accurate as possible then leave off the bs=4k option and it will default to 512-bytes - but this will take a very long time to clone.

The clone will take a number of hours, especially if you are hooking up the drives via USB adapter.