Does heads count different make drives difference?

Posted on 2012-09-05
Medium Priority
Last Modified: 2012-09-05
Hi there,

I am using two Seagate drives ST31500341AS to create RAID 1 system in a NAS system.

However NAS reported that two drives are not identical. From the fdisk -l I got following info. - heads count and sector count are different.

Disk /dev/sdb: 1500.3 GB, 1500301910016 bytes
255 heads, 63 sectors/track, 182401 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: 0x00000000

Disk /dev/sda: 1500.3 GB, 1500301910016 bytes
256 heads, 63 sectors/track, 181688 cylinders
Units = cylinders of 16128 * 512 = 8257536 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

My question is why does the drives with same model and same firmware come with different specs, and are they really different?

Is there anything I can do to make them identical?
Question by:tomcattyy
  • 2
LVL 13

Accepted Solution

Norm Dickinson earned 1200 total points
ID: 38369106
That may be a difference in the way the partitions were created, so if you delete all the partitions and start over using the same method for both drives, they may very well be seen as identical again.
LVL 47

Assisted Solution

David earned 800 total points
ID: 38369121
The number of heads reported by the O/S is virtualized/emulated. They mean nothing. Ignore the values.

It doesn't buy you anything making the count identical, but this can be done with a mode page editor.

Ignore the issue. It is of no consequence.

Author Comment

ID: 38369485
I end up place both disks into a PC and format as NTFS to eliminate the original partition and get the RAID 1 system get going.

Thanks for all the info.
LVL 13

Expert Comment

by:Norm Dickinson
ID: 38370512
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