Partition and large disk

I just (Sept 2013) hit a problem that needs some warning.

I buy a new hosted server with 2Tb hard drive. It was hired with openSUSE 12.3. Gladfully, I first tested the server and it's config.

When delivered, the partitionning was a bit curious:

/dev/sda1 / 10 Gb
/dev/sda2 /home 1.81 Tb
/dev/sda3 swap 512 Mb
/dev/sda4 1004 Kb grub boot

And, by the way, GPT organisation. Why "grub boot" and why on sda4? I don't know, but this is what was a problem.

May be it could be solved by hand, but YaST couldn't. I had to add some partitions for OS management. I could reduce the large sda2 partition, create small (30 Gb) partitions with YaST, but them Yast didn't anymore want to update the boot sector, nor wanted grub-install do it and so the computer become un-bootable. I suspect grub need some partition number on physical sort, and the new ones being before the grub one did no more find his, but why this couldn't be fixed with grub-install, I don't know.

My host provider (kimsufi.com) allows unlimited OS reinstall (and even change), So I tryed this, but impossible to only reload the system partition, the reinstall system do not know about GPT!

I have an other hosted server (in fact the old one, not yet closed), so I could backup the relevant data and reconfigure all the new server. With the kimsufi interface I choosed default install and got normal BIOS partitions and could have primary for / and swap, all the rest in extended and then anything I need.