Arch Linux

6arms1leg

Member

Registered: 2011-04-19

Posts: 22

[SOLVED] Install GRUB2 to post-MBR gap in BIOS system

i want to upgrade my current system to grub2 on my notebook (thinkpad with bios and "standard" msdos partitioning), but the wiki states that for mbr installation it is recommended to have a post-mbr gap of about 1-2 mib for grub's core.img.

 $ sudo parted /dev/sda print 

gives me:

Model: ATA SAMSUNG HM500JI (scsi)
Disk /dev/sda: 500GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags: 

Number  Start   End    Size   Type     File system  Flags
 1      32.3kB  197MB  197MB  primary  ext2         boot
 2      197MB   500GB  500GB  primary               lvm

so i only have ~32 kb. what is the best way to increase the post-mbr gap (moving the start point of my boot partition and shrinking the boot partition) without wiping the whole disk and reinstalling arch?

i thought about:
- creating a tar archive of all files on my boot partition and storing it somewhere save
- deteleting the old boot partition and creating a new one with a slightly bigger starting point (+creating the ext2 filesystem again)
- moving all files inside the tar archive back to my new boot partition
- upgrading/installing grub2 to mbr (following the wiki)

is that a good idea? is there a simpler way? there must be a lot of people out there having the same problem (since bios systems are still most common). so how did you installed grub2 to your running arch system?

thanks for your help!

Last edited by 6arms1leg (2012-08-22 16:08:00)

hadrons123

Member

From: chennai

Registered: 2011-10-07

Posts: 1,249

Re: [SOLVED] Install GRUB2 to post-MBR gap in BIOS system

You can upgrade to grub2 with current config without adjusting anything. Just upgrade.

Last edited by hadrons123 (2012-08-20 14:24:08)

6arms1leg

Member

Registered: 2011-04-19

Posts: 22

Re: [SOLVED] Install GRUB2 to post-MBR gap in BIOS system

thanks for your help!

i think that also depends on the size of the core.img. you are right, in my (simple) setup the post-MBR gap would have been big enough, but i wanted to be prepared for the future, in case grub gets any bigger. if anybody else is as paranoid as i am and has a similar setup, the procedure proposed in my first post works just fine.

DarioP

Member

From: Geneva

Registered: 2011-01-05

Posts: 165

Re: [SOLVED] Install GRUB2 to post-MBR gap in BIOS system

I wanted to update to GRUB2 but the wiki article got me confused.. Here is my partition table:

Model: ATA ST9500420AS (scsi)
Disk /dev/sda: 500GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags: 

Number  Start   End    Size   Type     File system  Flags
 1      32,3kB  23,1GB  23,1GB      primary   fat32           hidden, lba
 2      23,1GB  148GB   125GB       primary   ntfs            boot
 3      148GB   500GB   352GB       extended
 5      148GB   148GB   314MB       logical   ext2
 6      148GB   180GB   31,5GB      logical   ext4
 7      180GB   494GB   315GB       logical   ext4
 8      494GB   500GB   5661MB      logical   linux-swap(v1)

The first two partitions hosts windows 7 and recovery. I really don't want to move them as the risk to break up everything is very high. Should I install GRUB2 without touch the partition table? Will it break up in the future? Thanks...

EDIT: it will probably be ok without raid

Last edited by DarioP (2012-08-25 07:50:31)