Re: cloning a disk

On 8/8/26 10:52, mick.crane wrote:
> So the Linux OS disk is OK and it's the 2.7TB disk has wonky Backup GPT 
> Header
> The other error message is about the clone having a Backup GPT Header in 
> the wrong place.


I agree.


> What I still don't know is if the Backup GPT Header can be on the end of 
> a partition or a special GPT part at the end of the disk outside the 
> primary partition.


AIUI the protective MBR, primary GPT header, and primary GPT table 
occupy the first 34 blocks of a disk and the secondary GPT table and 
header occupy the last 33 blocks of a disk:

https://en.wikipedia.org/wiki/GUID_Partition_Table


I agree that the partitions must not overlap any of the above.  A proper 
GPT tool should enforce this requirement when resizing partitions.


> In which case for the clone I should backup the primary GPT Table, 


Backups are good.


> then extend the
> OS partition somehow without overlapping the backup GPT header.


If you go the clone, resize partition, and resize file system route.


> For the 2.7TB it is probably safer to sensibly prepare another ~3TB disk 
> and copy the files across.


That should work, but fixing the 3 TB HDD with gdisk(8) would be faster:

https://lists.debian.org/debian-user/2026/08/msg00053.html


David