Convert Windows 2012 R2 -- Legacy to UEFI ?

My Dell PowerEdge R610 is currently in
Legacy mode with four of the six bays full.

Each bay can hold a 600GB disk, therefore
I was thinking about doing six disks in RAID6,
giving me 2.4TB usable space, but I think
I need to switch to UEFI, correct ?

How can I easily switch
from Legacy to UEFI ?
  ** maybe a backup, reconfig, restore ?
Test #1 --> shows I am running Legacy

1. Control Panel
2. Administrative Tools
3. Computer Management
4. Disk Management
5. right-click Disk 0
6. select Properties
7. select Volumes TAB
8. Partition style:
     ** Master Boot Record (MBR) --> old style
     ** GUID Partition Table (GPT) --> new style, UEFI mode
Test #2 --> shows I am running Legacy

1. CMD
2. diskpart.exe
3. list disk
4. * under GPT column
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No, there is no need to use UEFI. That would only be necessary if you wanted to boot from a disk larger than 2 TB, which makes no sense at all, as the OS fits nicely onto a disk that is 100GB or smaller, and the OS should always be separate from data anyway. The data disk can be a GPT disk also when you aren't using UEFI. Most RAID controllers also can split an array into several volumes. So if your array is larger than 2TB, create 2 volumes, one a small one for the OS, and the other a large one for the data. The volumes will appear as separate disks to the OS, sou you can make the first volume an MBR disk and the other a GPT disk.

Booting from GPT in my point of view makes no sense and only complicate matters.

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noxchoGlobal Support CoordinatorCommented:
Is your OS installed on a drice which is over 2TB? If not then you dont need to convert anything. If yes then you need either to reinstall the OS because you are using only 2TB of avaialble space.
finance_teacherAuthor Commented:
I assume the below is good ?

1. install small Windows 2012 R2
   VM host on Master Boot Record
   (MBR) old style RAID-1 array
   of two hard drives
2. install all programs, VMs, data, etc
    on 3TB+ RAID-10 array of remaining
    hard drive bays
       ** can be Master Boot Record
             (MBR) old style or GUID Partition
             Table (GPT) new style UEFI mode,
             does not matter since this
             is not the BOOT drive ?
3. backup each separately
4. if either RAID has multiple hard drive
   failures I can then insert new hard drives
   and restore from Symantec BackupExec backup tapes
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You 3TB array must be GPT, or you will only be able to access 2TB of it's space. But since it isn't needed to boot from, you don't need an UEFI BIOS to be able to access the GPT disk from your OS.

The rest is OK.
finance_teacherAuthor Commented:
How can I easily switch
 from Legacy to UEFI ?
   ** maybe a backup, reconfig, restore ?
You don't need to switch to UEFI. UEFI is only needed if you are going to boot Windows from a GPT disk. Since you are booting to an MBR disk stay with Legacy BIOS.
noxchoGlobal Support CoordinatorCommented:
Why do you want to switch from legacy to efi and vice versa? Note, there is no easy way if once the data and OS are installed. You would need for it a third party tool. Because Microsoft requires the drive to be empty and unpartitioned to convert it to GPT or MBR.
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Windows Server 2012

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