Adjust partition table (end cylinder) after disk change.

noisebleed · 12-28-2007, 10:51 AM

Hi,

I have replaced my disk of 40 GB for a new one of 80 GB.

The copy was done using:

Code:

# dd if=/dev/sda of=/dev/sdb conv=notrunc,noerror

The partition table on the 40 GB disk is;

Code:

noisebleed ~ # fdisk -l

Disk /dev/sda: 40.0 GB, 40007761920 bytes
255 heads, 63 sectors/track, 4864 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1           9       72261   83  Linux
/dev/sda2              10         134     1004062+  83  Linux
/dev/sda3             135        2002    15004710   83  Linux
/dev/sda4            2003        4864    22989015    5  Extended
/dev/sda5            2003        2625     5004216   83  Linux
/dev/sda6            2626        4864    17984736   83  Linux

In the 80 GB disk i have removed the sda6 partition and recreated it with less 64 cylinders. Then i created sda7 with the remaining space:

Code:

noisebleed ~ # fdisk -l

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1           9       72261   83  Linux
/dev/sda2              10         134     1004062+  83  Linux
/dev/sda3             135        2002    15004710   83  Linux
/dev/sda4            2003        4864    22989015    5  Extended
/dev/sda5            2003        2625     5004216   83  Linux
/dev/sda6            2626        4800    17470656   83  Linux
/dev/sda7            4801        4864    514048+   83  Linux

My problem is:

The end cylinder of partition sda7 is wrong. It should be 9729,

With this scheme i am loosing the new 40 GB of extra space.

How do I recover this?

Thanks.

Extra info:

Distro: Gentoo Linux

Filesystem: ext3

syg00 · 12-29-2007, 04:26 AM

Use cfdisk

noisebleed · 12-30-2007, 03:34 PM

Thanks for the reply.

The issue was my first logical partition (sda4) in which sda5, sda6 and sda7 are contained.

I have deleted sda4 and created it again recovering all the extra space available.

Now all 80 GB are available

syg00 · 12-30-2007, 04:39 PM

That's actually an extended partition, and yes it is the container for all logicals.
cfdisk is handy in that it will "expand" the underlying extended partition if the layout is appropriate - in your case it is. You could have just deleted and resized sda7, and the extended would have been handled for you automagically.
Note: cfdisk, not fdisk.

Of course the gparted livecd does all this and more (with a nice gooey as well).