I have installed centos 5.8 with Hetzner server rescue mode but its disk parttion table is in MSDOS formate which does not support more than 2 TB space of disk so i need to change the partition table into GPT formate.but enable to install os in Gpt formate how can i cange parttion table formate from dos to gpt. Thanks in advance.
Boot using RescueCD from Hetzner.
And next create LVMs, format partition and use VNC instalation.
You don't. GPT support is available on EL6, but not on EL5.
So Hetzner should never have offered you this distribution.
To resolve the issue, install CentOS 6 instead.