Re: How to clone to a smaller HDD without messing up partitions?

[Ketil Froyn]

I have a different suggestion. Set up your target device with some sort of
deduplication and/or compression. For example btrfs or zfs or vdo. Then you
can clone to a file on the target, and hopefully you'll have space for the
whole thing.

On Sat, Oct 26, 2019, 04:03 Shahrukh Merchant <address@hidden>
wrote:

> I have a 500 GB HDD (source) that I want to clone to a 320 GB HDD
> (destination). Both are MBR. Only about 60 GB of the source drive is
> actually in use (in 2 partitions), the rest (400+ GB) is in unallocated
> space.
>
> I will ask more specifically in two different ways:
>
> 1. I would like to tell ddrescue to clone the entire drive, i.e.,
>
> ddrescue -f -n /dev/sda /dev/sdb
>
> BUT with options that effectively say "and don't worry if you run out of
> space on the destination drive--just stop copying since the important
> stuff is at the start anyway." Can I do that, and how? (And other than
> relying on the Windows Disk Management visual to believe that the
> unallocated space is all at the end, which it seems to be, is there some
> other tool I can use to let me confirm that explicitly?)
>
> 2. If the answer to the above is "No" or "Not recommended," then I would
> have to do the clone partition by partition. There are two partitions on
> the source disk as follows:
>
> lsblk version
> -------------
> sda             465.8G
>   -sda1 RECOVERY   9.8G ntfs
>   -sda1 OS        54.9G ntfs
>
> Windows 7 Disk Management version
> ---------------------------------
> Disk0 Basic/465.76 GB/Online
> --------
> 9.77 GB
> Healthy (Active, Recovery Partition)
> --------
> OS (C:)
> 54.93 GB (NTFS)
> Healthy (Boot, Page File, Crash Dump, Primary Partition)
> --------
> 401.07 GB
> Unallocated
> --------
>
> So if I do the clone partition by partition, two things are not clear:
>
> (a) What is the sequence of commands I need to use (and how to I prepare
> the destination drive in advance). Can I do, for example:
>      ddrescue -f -n /dev/sda1 /dev/sdb
>      ddrescue -f -n /dev/sda2 /dev/sdb
> and have ddrescue figure out that I mean "put them in their
> corresponding places on the destination drive based on how it was on the
> source drive and fix the MFT so it does the right thing" (seems a lot to
> ask for, but maybe it does!)?
>
> (b) How do I maintain the integrity of the destination drive w.r.t. the
> MFT of that drive being properly configured (since it is not part of the
> ddrescue copy, as I understand it, if I do a partition at a time), and
> in terms of the destination drive booting fine in exactly the same way?
>
> Basically, the unallocated space at the end is the only part that I want
> to be different, owing to the different in drive sizes.
>
> Thanks!
>
> Shahrukh
>
>