[DRBD-user] Reproduceable error - creating a single directory causes drbd to fail

[Graham Wood]

> Definitely missing something there.

The raw device is (say) 1024MB.
The drbd device is (say) 896MB (128MB metadata, IIRC).

Therefore if you mkfs the raw device, it'll create a file system based  
on 1024MB.  Mounting the filesystem via the drbd device will give you  
a block device that's only 896MB in size.

Therefore any attempt to access the data between 896MB and 1024MB will  
fail since that just doesn't exist anymore.

That's why you should do all of the block level work /before/ doing  
anything else.  EVERYTHING to do with user data should be done solely  
via the /dev/drbd<n> device.

Of course, I could be misunderstanding your problem.

Graham