Partition 1 does not start on physical sector boundary

[davidmaxwaterman]

Hi,

I'm trying to (re)make a 3 disk RAID5 array using mdadm. I previously was using whole disks, but I have been advised to use partitions. Unfortunately, when I use fdisk to make the partitions, I get the error :

Partition 1 does not start on physical sector boundary

That's for only two of the disks and happens when I try to 'p' the partition table after having created partition 1 as primary using default start and end values.

I read the Linux-FAQ/error-messages.html, but it doesn't have the exact error message.

I'm using fdisk (util-linux-ng 2.17.2) on ubuntu 11.04/2.6.38-11-generic-pae.

Here is the fdisk -l output for the relevant disks (without partitions, of course) :

# fdisk -l /dev/sd[cde]

Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00098452

   Device Boot      Start         End      Blocks   Id  System

Disk /dev/sdd: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x000ca99c

   Device Boot      Start         End      Blocks   Id  System

Disk /dev/sde: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x00028409

   Device Boot      Start         End      Blocks   Id  System

I lost the previous contents (I think) due to some partition problem, so I want to get it right this time before I restore from backup.

Any ideas?

[Lazydog]

Which disk is giving you the problem?

[davidmaxwaterman]

Which disk is giving you the problem?

sdc doesn't give the 'error', but sd[de] do.

[rcgreen]

Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00098452

Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x000ca99c

They are using different sector sizes. You may need to use a newer partitioning tool
that can create the partitions so that they align. Apparently this means that
the number of sectors must be divisible by 8.

What is a physical 'sector' boundary? - alt.os.linux | Google Groups

[Lazydog]

Good catch. That one slipped by me.