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kevdog

Member

Registered: 2013-01-26

Posts: 102

[SOLVED] Converting MBR to GPT

I've read a lot prior to beginning this process, however I think I'm stuck

I started out with a MBR:

$ sudo fdisk -l
Disk /dev/sda: 400 GiB, 429496729600 bytes, 838860800 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xb96d5e96

Device     Boot     Start       End   Sectors   Size Id Type
/dev/sda1  *         2048    391167    389120   190M 83 Linux
/dev/sda2          391168   7813119   7421952   3.6G 82 Linux swap / Solaris
/dev/sda3         7813120 300781567 292968448 139.7G 83 Linux
/dev/sda4       300781568 836812799 536031232 255.6G 83 Linux

Prior to converting to a gpt partition table, I ensured there was enough room on the end of the drive, and ensured the /boot partition (/dev/sda1) began at the 2048 Mb boundary
I generated the the gpt partition table from the mbr partition table using gdisk. Following the arch wiki: Arch Wiki GPT
to generate a bios boot partition (as instructed).  After the conversion and the addition of the BIOS Boot partition, I have the following:

Partition Table Scan:
 MBR: protective
 BSD: not present
 APM: not present
 GPT: present

Found valid GPT with protective MBR; using GPT
Disk /dev/sda: 838860800 sectors, 400.0 Gib
Logical Sector Size: 512 bytes
Disk identifier (GUID): E84CC0D5-C7CF-4606-B6C9-6266E1F2866C
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 838860766
Partitions will be aligned on 8-sector boundaries
Total free space is 2047967 sectors (1000.0 MiB)

Number     Start (sector)       End (sector)          Size          Code   Name
     1                2048              391167        190.0 MiB      8300    Linux filesystem
     2              391168            7813119         3.5 GiB         8200    Linux swap
     3             7813120         300781567        139.7 GiB      8300    Linux filesystem
     4          300781568        836812799        255.6 GiB      8300    Linux filesystem
     5              34               2047             1007.0 KiB    EF02    BIOS boot partition

After writing the partition table to disk, I booted into live CD, chrooted with arch-chroot, and reinstalled grub

# grub-install --recheck --target=i386-pc /dev/sdx
# grub-mkconfig -o /boot/grub/grub.cfg

With the grub-mkconfig command I get the following error: EXT4-fs (sda5): VFS: Can't find ext4 filesystem

However when booting -- it will not boot.

Was I supposed to format the BIOS boot partition with ext4?
Any other advice would be very helpful

Last edited by kevdog (2016-01-31 00:09:34)

kevdog

Member

Registered: 2013-01-26

Posts: 102

Re: [SOLVED] Converting MBR to GPT

I repeated the process again -- exactly as described.  For some reason it worked -- system booted.  Reports the following as before:

sudo gdisk /dev/sda
GPT fdisk (gdisk) version 1.0.1

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.

Command (? for help): print
Disk /dev/sda: 838860800 sectors, 400.0 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): E84CC0D5-C7CF-4606-B6C9-6266E1F2866C
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 838860766
Partitions will be aligned on 8-sector boundaries
Total free space is 2047967 sectors (1000.0 MiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048          391167   190.0 MiB   8300  Linux filesystem
   2          391168         7813119   3.5 GiB     8200  Linux swap
   3         7813120       300781567   139.7 GiB   8300  Linux filesystem
   4       300781568       836812799   255.6 GiB   8300  Linux filesystem
   5              34            2047   1007.0 KiB  EF02  BIOS boot partition

Hopefully someone will find this information useful.  Hours of reading for a process that in actuality takes a few minutes to perform.

Last edited by kevdog (2016-01-13 06:12:11)

satanselbow

Member

Registered: 2011-06-15

Posts: 538

Re: [SOLVED] Converting MBR to GPT

Hopefully someone will find this information useful.  Hours of reading for a process that in actuality takes a few minutes to perform.

Welcome to linux

tyrannis

Member

Registered: 2015-11-06

Posts: 94

Re: [SOLVED] Converting MBR to GPT

If you issue has been resolved, please edit your original post and add [SOLVED] to the beginning of the title.