512 byte problem

[Snowhog]

Today I attempted to do what I've done many times previously: clone my internal HDD to my external USB HDD. I use Clonezilla, and today it refused, saying that the source HDD was larger than the target HDD. Huh?? My internal drive 'grew' or my external drive 'shrunk'!? Not likely. However, fdisk -l does show a 512 byte difference between the two HDDs. How did this happen!?

Disk /dev/sda: 500.1 GB, 500107862016 bytes

255 heads, 63 sectors/track, 60801 cylinders, total 976773168 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: 0xf4aea3a7

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *        2048     8390655     4194304   82  Linux swap / Solaris

/dev/sda2         8392702   417349631   204478465    5  Extended

/dev/sda5         8392704    39849983    15728640   83  Linux

/dev/sda6        39852032   144709631    52428800   83  Linux

/dev/sda7       144711680   176168959    15728640   83  Linux

/dev/sda8       176171008   281028607    52428800   83  Linux

/dev/sda9       281030656   312487935    15728640   83  Linux

/dev/sda10      312489984   417347583    52428800   83  Linux



Disk /dev/sdc: 500.1 GB, 500107861504 bytes

255 heads, 63 sectors/track, 60801 cylinders, total 976773167 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: 0xf4aea3a7

   Device Boot      Start         End      Blocks   Id  System

/dev/sdc1              63   976768064   488384001   83  Linux

Both HDDs have the same geometry: 255 heads, 63 sectors/track, 6081 cylinders, but there is a one sector difference (512 bytes) between them. If the geometry's are the same, how can a sector be missing?

[tnorris]

The only thing I can think of off hand is that one sector got marked bad by the drive via SMART. You can check the smart status of the drive w/ the "smartctl" command.