I'm trying to install RHEL 5.8 x64 on Cisco UCS C240 server with 4TB OS Drive. The drive is behind LSI MegaSAS.

Before installing RHEL, I booted off from an Ububtu 14.04 Live DVD. Using gparted, initialized the disk with GPT table, and few 20GB partitions.

I went back to install RHEL5 and got following error right after telling anaconda to install on pre-existing partitions (with GPT label):

Your boot partition is on a disk using the GPT partitioning scheme but this machine cannot boot using GPT

Screenshot is below:


Is there any other way to use the 4TB disks or have to downgrade to <= 2TB disks?


According to Redhat the disk label should be changed to MSDOS:

GPT must be switched to MSDOS. This will cause a loss of all current data on disks as well as limiting the device size to 2 TB

1. At the partitioning screen, press Ctrl + Alt + F2 to get to a shell prompt.

2. Overwrite the GPT partition label with an MSDOS label.

[root@host ~]# parted /dev/sda -s mklabel msdos

3. Press Ctrl + Alt + F6 to return to the partitioning screen, and continue installation, it
may be needed to back one step up in order for the installer to see the new changes.

Root Cause

  • The GRand Unifed Bootloader (GRUB) is not compiled with the ability to utilize GPT partitions in RHEL5.
  • The MSDOS partition label will allow GRUB to boot correctly, but has a physical limitation of 2 TB.
  • This above error was a check added in RHEL 5.2.
  • In 5.0 and 5.1, the installation would continue but the ending install will not boot.

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