I'm tring to back up the partition table of a Linux Ubuntu 10.04 LTS.
Actually I'm making the tests with Virtualized machines (VirtualBox). And I have one source system in a virtual disk, another virtual machine as the rescue system, and another empty virtual disk with the same size exactly than the source system disk.
So, running the rescue system I mount the source system disk and user this command for making the partition table backup:
sfdisk /dev/sdb –d > /backup/sdb-part-table.sf
And the file gets generated and saved with this output message:
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Once I Have the partition table file I unmount the source disk and mount the backup empty disk.
I try to use this command:
sfdisk /dev/sdb < /backup/sdb-part-table.sf
Then I try again to restore the parition table but gives me this error:
Checking that no-one is using this disk right now ...
OK
Disk /dev/sdc: 265 cylinders, 255 heads, 63 sectors/track
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Old situation:
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0
Device Boot Start End #cyls #blocks Id System
/dev/sdc1 * 0+ 245- 246- 1973248 83 Linux
/dev/sdc2 245+ 265- 20- 155649 5 Extended
/dev/sdc3 0 - 0 0 0 Empty
/dev/sdc4 0 - 0 0 0 Empty
/dev/sdc5 245+ 265- 20- 155648 82 Linux swap / Solaris
New situation:
Units = sectors of 512 bytes, counting from 0
Device Boot Start End #sectors Id System
/dev/sdc1 * 2048 3948543 3946496 83 Linux
/dev/sdc2 3950590 4261887 311298 5 Extended
/dev/sdc3 0 - 0 0 Empty
/dev/sdc4 0 - 0 0 Empty
/dev/sdc5 3950592 4261887 311296 82 Linux swap / Solaris
Warning: partition 1 does not end at a cylinder boundary
sfdisk: I don't like these partitions - nothing changed.
(If you really want this, use the --force option.)
So Finally I user force to make the restoration and seem to work:
sfdisk --force /dev/sdb < /backup/sdb-part-table.sf
Getting this result:
Checking that no-one is using this disk right now ...
OK
Disk /dev/sdc: 265 cylinders, 255 heads, 63 sectors/track
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
Old situation:
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0
Device Boot Start End #cyls #blocks Id System
/dev/sdc1 * 0+ 245- 246- 1973248 83 Linux
/dev/sdc2 245+ 265- 20- 155649 5 Extended
/dev/sdc3 0 - 0 0 0 Empty
/dev/sdc4 0 - 0 0 0 Empty
/dev/sdc5 245+ 265- 20- 155648 82 Linux swap / Solaris
New situation:
Units = sectors of 512 bytes, counting from 0
Device Boot Start End #sectors Id System
/dev/sdc1 * 2048 3948543 3946496 83 Linux
/dev/sdc2 3950590 4261887 311298 5 Extended
/dev/sdc3 0 - 0 0 Empty
/dev/sdc4 0 - 0 0 Empty
/dev/sdc5 3950592 4261887 311296 82 Linux swap / Solaris
Warning: partition 1 does not end at a cylinder boundary
Successfully wrote the new partition table
Re-reading the partition table ...
If you created or changed a DOS partition, /dev/foo7, say, then use dd(1)
to zero the first 512 bytes: dd if=/dev/zero of=/dev/foo7 bs=512 count=1
(See fdisk(8).)
But, when I move the backup to the new file system witch seem to be alright, the system do not start, I have a black screen as if no OS where installed in the backup machine, comparative of Partition Tables are equal in the working source disk and in the backup not-working disk.
Mbr backup is already done and installed. I've tried to install after and before the partition table restoration.
So, any idea of how can I make it work?
Thanks in advance, and have a nice week :D
