I have a Dell Poweredge r710 server with five 1 TB disks. All of them are in RAID 5. I was trying to install Centos but it says "Your boot partition is on disk using GPT Partition..."

I read somewhere that centos can't install on a disk larger than 2TB, so I made some partitions smaller, but it's not working.

PS, I am going to install Proxmox on that, but Proxmox also won't accept disks larger than 2TB.

3 Answers 3


Use LVM, not partitions

The problem is that GRUB or other parts of the boot process work only with 'traditional' DOS partitions, which are limited to handling 2TB volumes. Making some partitions smaller doesn't help, because the problem is with the partition table, not the partitions.

LVM is better supported than GPT, and it's far more flexible. Honestly, you shouldn't be using partitions on anything around a TB or more.

Before somebody objects: yes, you can use LVM on the 'raw' devices without any partition table.


EL5 didn't really support GPT partitions. Support for GPT was added in EL6, which was released after you wrote this question..

On EL6, if your system uses a legacy BIOS, then you can only use GPT on drives other than the boot drive; the boot drive must still use MBR. If you want to use GPT on your boot drive, your server/workstation must have UEFI.


If you use 1T VirtualDisk for the OS (CentOS) and 4x1TB in RAID5 VirtualDisk for data, you can install CentOS on the 1TB disk and it should be smooth.

I've installed CentOS 6.3 (efi) on 2T disk without any problem.

  • ...and your OS drive ends up with no fault-tolerance. not a good idea.
    – longneck
    Oct 8, 2012 at 13:10

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