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I have pretty old (~8 years) Supermicro server, which just got 4T new disk (actually it may be even bigger, because we are considering update to 5T or maybe even RAID 12T).
I'm trying to install some modern OS, which can boot both from MBR or from EFI. However if I go MBR, this limits my total available space by 4T (2x2T msdos partition size), if I set GPT partition, BIOS doesn't recognize boot sector and EFI of course.
Is there any way to boot EFI OS over MBR and don't lose space on the disk? In other words, is it possible to boot EFI from GPT partition on the MBR computer?
I know that GPT can work in hybrid mode, so I thought to set there GRUB and from GRUB, boot the main OS over EFI..... But I'm not sure that grub can boot EFI. Also it looks very kludgy....
rth
Posted 2019-03-29T19:27:08.433
Reputation: 101
You may find this answer interesting, especially where the cited text reads "… gives a total size approaching 4 TiB".
– Kamil Maciorowski – 2019-03-29T20:05:34.057msdos partition sizeDOS doesn't support such big drives. In fact many versions have problem with 2GB or 8GB drives, let alone 2TB.I set GPT partition, BIOS doesn't recognize boot sectorBIOS doesn't know about hard drive format, so it can recognize neither MBR or GPT. It simply loads the first sector and transfer control to the boot sector program, so BIOS can boot GPT disks without problem, as long as there's a supported bootloader. Oh and MBR can support disks bigger than 2TB with 4K cluster (A.K.A advanced format), or 4TB minus a few KB with 512-byte sectors – phuclv – 2019-04-02T16:29:19.2431
depending on which modern OS you're talking about, it'll be a duplicate of Is it possible to boot Linux from a GPT disk on a BIOS system? or Is there any way to boot Windows 7/8 using BIOS on GPT?. See also Make 3TB hard drive appear as two (2TiB+750GiB) with MBR, How do I split a 3TB disk into two 1.5TB disk partitions?
– phuclv – 2019-04-02T16:31:52.297