Arch Linux

Ipozya

Member

Registered: 2011-01-20

Posts: 52

grub on backup (error 21)

Hi,
I have followed these instruction to backup my system https://wiki.archlinux.org/index.php/Fu … with_rsync
Everything has worked great and I edited my /etc/fstab on the backup (on my external hard drive) and am now at the part where I told to install a bootloader.  The external hard drive is /dev/sdb1 but I get the following error:

$grub
grub > root (hd1,0)
Error 21: Selected disk does not exist

I also tried the geometry option to see the layout but same error:

grub > geometry (hd1)
Error 21: Selected disk does not exist
grub > geometry (hd0)
Error 21: Selected disk does not exist

Any suggestions? Thank you very much.

Spider.007

Member

Registered: 2004-06-20

Posts: 1,175

Re: grub on backup (error 21)

what is the output of this command?

fdisk -l /dev/sdb

Last edited by Spider.007 (2011-03-26 12:03:46)

Ipozya

Member

Registered: 2011-01-20

Posts: 52

Re: grub on backup (error 21)

#fdisk -l /dev/sdb
Note: sector size is 4096 (not 512)

Disk /dev/sdb: 3000.6 GB, 3000558944256 bytes
255 heads, 63 sectors/track, 45599 cylinders, total 732558336 sectors
Units = sectors of 1 * 4096 = 4096 bytes
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x0002dcc8

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1             256   732558335  2930232320   83  Linux

I am actually wondering, are those last two parts of the guide necessary?  After doing rsync, I have all of the files that I want backed up on the external hard drive.  I don't necessarily need to make the hard drive bootable by changing fstab and installing grub.  After just backing up files to hard drive, would it still be possible to restore system if I wanted?

Last edited by Ipozya (2011-03-26 22:38:56)

Spider.007

Member

Registered: 2004-06-20

Posts: 1,175

Re: grub on backup (error 21)

If you do not need the backup to be bootable, the last steps are indeed not required. Would you restore from the backup, you would need to manually install grub afterwards, but you would need to do that anyway.