Ubuntu – How to make a copy of an installed Ubuntu machine’s packages, without internet access

The problem is that apt/dpkg can't look inside the image files for the .deb package files. You need to get the .deb files themselves to your USB source.

I would do this as follows:

1. Install Ubuntu server on another computer (or into an empty partition or into a virtual machine) that does have a network connection.
2. Run 'aptitude clean' to clear out the package directory at /var/cache/apt/archives
3. Run 'aptitude install xfce'
4. /var/cache/apt/archives will now have the .debs you need. Copy these over to your drive and run the install on the original computer.

There's also a program called apt-offline that that handles this kind of situation but probablly not worth learning for just one install.

Yes, they'll all work fine because the MD superblock contains a UUID identifying the drives as all belonging to the same RAID volume. When you tell mdadm to auto-assemble, it scans all block devices and will find the MD superblocks and put the volume back together again.