Partitioning for GPT (and GRUB2)

Llama · 2015-09-06 12:43:19

Hi,

I'm now in the process of cloning my old system to a new hard drive. The old drive (1.5Tb) used MBR, the new one (3.0Tb) can't. No big deal, I'm cloning by partition.

The old (source) one:

sda1 Swap
sda2 ext4 /
sda3 ext4 /home

This is the simplest possible scheme, I always use it. I meant to retain it, but this does not seem exactly possible: ArchWiki. It looks like I have to create a new fat32 partition. Is that really so? Does it have to look something like this? I am not sure.

sda1 Swap
sda2 fat32 /boot
sda3 ext4 /
sda4 ext4 /home

If so, how big the fat32 partition should be? I'm using gparted; it acknowledges GPT, but says nothing about the fat32 partition.

Ah, yes, with gparted I do have to create the separate fat32 partition. Still, the questions remain: does it have to be mounted as /boot? How big should it be?

Trilby · 2015-09-06 12:49:51

Do you intend on uefi booting or bios booting? If the latter, that is the wrong section to follow: https://wiki.archlinux.org/index.php/GR … structions

Llama · 2015-09-06 13:57:18

Trilby wrote:

Do you intend on uefi booting or bios booting? If the latter, that is the wrong section to follow: https://wiki.archlinux.org/index.php/GR … structions

BIOS, probably . I tried to create

sda1 Swap
sda2 ext4 /
Unformatted partition #1 (2Mb)
sda3 ext4 /home

with gparted, but it won't wash. What am I exactly to do?

Though BIOS_GRUB flag is mentioned in gparted docs.

Last edited by Llama (2015-09-06 14:00:14)

Trilby · 2015-09-06 14:14:55

What does "it won't wash" mean? What errors do you get at which stage?

Why did you make the unformatted parition 2Mb? If you actually mean 2Mb that is not big enough - if that was 2 MB, then that is double what is recommended. I doubt having too much space there would be a problem, but why are you not just following the instructions in the wiki?

Llama · 2015-09-06 14:24:32

Trilby wrote:

What does "it won't wash" mean? What errors do you get at which stage?
Why did you make the unformatted parition 2Mb? If you actually mean 2Mb that is not big enough - if that was 2 MB, then that is double what is recommended. I doubt having too much space there would be a problem, but why are you not just following the instructions in the wiki?

Won't wash means that without errors it ends up like

sda1 Swap
sda2 ext4 / (30Gb)
sda3 ext4 (2Mb)
sda4 ext4 /home (2Tb)

Despite my telling explicitly to leave the 2Mb unformatted.

UPD:

Somehow managed with gparted:

sda1 unknown (1Mb) bios_grub ;; "cleared" instead of "unformatted"
sda2 Swap (512Mb)
sda3 ext4 (48Gb)
sda4 ext4 (2.7Tb)

Let's see how far this will take me

Last edited by Llama (2015-09-06 14:38:40)

Head_on_a_Stick · 2015-09-06 16:59:16

Please post the output of:

# gdisk -l /dev/sda

Non-EFI ("BIOS") booting on a disk with a GUID partition table is firmware dependent and may not work at all.
https://wiki.archlinux.org/index.php/GU … OS_systems

If your drive uses 4096-byte sectors you can still use an MBR-style partition table for disks up to 16TiB
http://www.rodsbooks.com/gdisk/workarounds.html

Llama · 2015-09-06 19:51:53

(Yes, it's actually sdb)

$ sudo gdisk -l /dev/sdb
GPT fdisk (gdisk) version 1.0.0
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Disk /dev/sdb: 5860533168 sectors, 2.7 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): AD8947AD-6F22-4255-94FA-DBD26F6551BC
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 5860533134
Partitions will be aligned on 2048-sector boundaries
Total free space is 2925 sectors (1.4 MiB)

Number Start (sector) End (sector) Size Code Name
1 2048 4095 1024.0 KiB EF02
2 4096 1052671 512.0 MiB 8200
3 1052672 103452671 48.8 GiB 8300
4 103452672 5860532223 2.7 TiB 8300

Head_on_a_Stick · 2015-09-06 20:08:32

^ Looks good, go for it.

As I say though, there is no guarantee of success in respect of booting in non-EFI mode on a GPT disk even if the procedure is correct.

Arch Linux

#1 2015-09-06 12:43:19

Partitioning for GPT (and GRUB2)

#2 2015-09-06 12:49:51

Re: Partitioning for GPT (and GRUB2)

#3 2015-09-06 13:57:18

Re: Partitioning for GPT (and GRUB2)

#4 2015-09-06 14:14:55

Re: Partitioning for GPT (and GRUB2)

#5 2015-09-06 14:24:32

Re: Partitioning for GPT (and GRUB2)

#6 2015-09-06 16:59:16

Re: Partitioning for GPT (and GRUB2)

#7 2015-09-06 19:51:53

Re: Partitioning for GPT (and GRUB2)

#8 2015-09-06 20:08:32

Re: Partitioning for GPT (and GRUB2)

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