Why does fdisk create partition at 2048 instead of 63?

[littlebigman]

Hello

On a test host that has two partitions (one to hold the OS, the second to hold images made with Clonezilla), partition #1 used to start at sector 63.

I had an issue booting with Windows7, so I deleted partition #1. But now, when I run fdisk to recreate the partition, fdisk won't let me choose 63 as the start sector but instead use 2048... which is too small and Clonezilla refuses to restore a new image.

Does someone know what could explain this change, and how to solve this issue?

Before, when cloning Windows7

Model: ATA WDC WD3200BEVT-2 (scsi)
Disk /dev/sda: 625142448s
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start       End         Size        Type     File system  Flags
 1      63s         537358184s  537358122s  primary  ntfs         boot
 3      537358336s  625141759s  87783424s   primary  ext2

Now

Disk /dev/sda: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625142448 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
Disk identifier: 0xf1f75308

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1            2048   537358335   268678144    7  HPFS/NTFS/exFAT
/dev/sda2       537358336   625141759    43891712   83  Linux

Thank you.

[littlebigman]

No idea why fdisk did this, but removing all partitions and starting from scratch solved the issue.

[user503629]

No idea why fdisk did this, but removing all partitions and starting from scratch solved the issue.

For anyone else facing this issue, I wanted to recommend GNU parted. It is a command-line utility that will allow you to select any start value for your partition. In performing this operation, I wiped the MBR of my disk first (using dd), to avoid warning messages from parted about damaging the old filesystem(which I wanted to erase anyway).

If you want to preserve data on the existing filesystem, don't do this.

You may need to read the built-in help, and then by setting the units to sectors, you can match your previous start sector for the disk by typing:

(parted) mkpart
partition type? primary/extended? p
file system type? [ext2] ntfs (this will merely set the partition ID)
start? 63s ("s" means sector in parted)
end? 537358184s

There are reasons why the newer linux fdisk defaults to starting at 2048, and I suggest the reader find out about these (ie a software standard of dividing partitions on a 1MByte boundary, and also the arrival of some new drives with 4k sectors).

Even better for ext2 filesystems, this will make a partition fill the entire disk:

(parted) mkpart
partition type? primary/extended? p
file system type? [ext2] *hit enter* (this will merely set the partition ID)
start? 1s ("s" means sector in parted)
end? -1s (In parted, negative 1 means the very last sector)

(why waste unallocated sectors if you don't need compatibility with other OS?)

[jayd512]

Hi, user503629!
Great advice given there! Very similar to what I have told folks in the past.
The OP, however, hasn't been active since shortly after posting this question.
So I'll lock this down for now.

But please feel free to help out on any other threads that catxh your eye!