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

[Robert Backhaus]

Clever! Oh, you'll need to add --force to those command lines. ddrescue
needs that when you write to existing devices.

One thing I also usually do is install ddrescue-utilities, and use
ddru-ntfsbitmap to create a mapfile of all blocks containing data. Then you
pass that to ddrescue using -m (ddrescue -m file.map infile outfile
logfile). This means that ddrescue then only copies blocks containing data.

On Sat, 26 Oct 2019 at 19:06, Dr. Anonymous <address@hidden> wrote:

> There is one more way to do exactly you want! Without copying any unneeded
> sectors and without determining the exact sizes!
> Assuming /dev/sdc to be the source and /dev/sdb to be our destination.
> First, copy the MBR (the very first sector):
> ddrescue /dev/sdc /dev/sdb -s1s
> Then, either reboot the system or anyway make the kernel recognize the new
> MBR of the destination drive.
> Then copy the initial partitions to the destination:
> ddrescue /dev/sdc1 /dev/sdb1 ~/1.log
> ddrescue /dev/sdc2 /dev/sdb2 ~/2.log
> That's all.
>
> ----- Original Message -----
> From: "Ketil Froyn" <address@hidden>
> To: "Shahrukh Merchant" <address@hidden>
> Cc: "dd-rescue" <address@hidden>
> Sent: Saturday, October 26, 2019 10:30 AM
> Subject: Re: How to clone to a smaller HDD without messing up partitions?
>
>
> >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
> >>
> >>