How to

Clone Hard Disk with different sector size

Moving or restoring data from one medium to another is not as straight forward as it may seem. Advancement in hardware makes older hardware data to be moved harder.

Be warned! Expect everything, so back up your data before anything else.

Cloning at a bit level between two disks is the best way to get exact copy of your data. Currently, most of the newer hard disks have bigger sector size, so to clone from a smaller sector size hard disk will not be easy.

There are different tools that advertise cloning tasks, but none of them, at least till now, can do this job.

In our case, we had old 160GB hard disk with two partitions, one with W7 size100GB, and new WD 1TB disk.

Ubuntu LiveCD came our rescue as we did not want to boot from W7 which will be cloned. Linux has several tools and utilities to clone disks at a low level. if someone is sure data writing/reading similarities between disks, simply use dd command. But what about different sector sizes.

After booting from Ubuntu Live, we used to get disks information by sudo fdisk -l, if you pay attention to the starting and ending points, it is clear it is not possible to clone data directly from one disk to another.

W7 creates one small partition of about 100MB size used for boot and MBR, information from fdisk -l is that starting point of the old disk (sda) is 2048, but newer disk's (sdb) starting point is 256.

Simple address observation: newer disk (sdb) uses 4096B sector size (= 212), whereas older disk uses 512B sector size  (= 29), which will give us  23x size. But problem lies when you look into sector's starting points 2048/256 will give us 23. That in effect is 8:1.

Using currently available cloning tools then using Linux's gparted from LiveCD, new disk will have same number of partitions as the old disk, but with 8 times of their size, or at least its percentage proportion of the old disk. E. g. first partition of 75MB/100MB used/whole size will become 600MB/800MB. So, where all these 600MB data came from? Clearly data is unusable, and partitions are inaccessible.

Instead of filling newer disk sector cloned data from eight older disk sectors (because each sector can hold 8x data), cloning tools will disperse data into eight different sectors in the  newer disk as they clone sector by sector instead of data bits, that is what makes it difficult. It seems cloning tools are designed to count sectors instead of data size.

Only solution that worked for us was to

  • Install fresh installation of OS (tested W7 Professional, probably every other OS will work, including Linux flavours) on the newer disk (WD 1TB)
  • Use cloning utilities or tools (we used colenezilla)
  • Use old disk (160GB) as the source and newer disk (1TB with freshly installed OS) as the destination.

Voila, disk is cloned, filled exact data not 8x, your old partitions are same size, e.g. 100MB, 100GB, etc., but you have unallocated space (1TB - 160GB). Your new challenge will be how to extend your partitions.




Comments (2)
Farrel Joe

Thanks for your information, saved me from lot of trouble. I tried to clone, with expensive tools, but none helped me.
It is part of my job to do some data migrations, backup and clone, so you helped me a lot.
One advice, change your fonts or formatting. Anyway, thanks for your helpful post.
sunil

tried to follow your steps, but still could not clone.
can you, please give me simple steps to follow.
Thank your effort and information

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