Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

[The Woozy Fieldmouse]

The subject basically says it all. I'm rapidly becoming addicted to things like virtualization and server hosting and feel 4Gigs to be a little cramped. I've looked around a bit and read somewhere that you could just backup your home directory and restore it in the new install to get back all user files and desktop settings which is great, but is there some way to automatically backup and restore my packages? I know APTonCD will back them up, but I doubt it will restore them from a 32-bit system to a 64-bit. I also read that you can pretty easily install 32-bit packages on a 64-bit system, but what I really want is to install the 64-bit equivalents of the 32-bit packages. I suppose if worst came to worst I could install the 32-bit packs and then just replace only the big RAM-hogs with 64-bit variants (I'm thinking VirtualBox here). What do you think?

[dibl]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

"Migration" is the wrong paradigm. It is a replacement. You have to install the 64-bit architecture OS, and then you have to install the 64-bit packages you need. It's all automatic, there's nothing that the user needs to do "differently". Your data are fine -- there is no impact on your data files.

[GreyGeek]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

I'm with Dibl on this.

Personally, what I do is backup my important files, configurations, etc..., and then do a FRESH install of the 64bit ISO. Then restore the backed up files and configs. That will give you the cleanest install with the least problems.

[The Woozy Fieldmouse]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

Okay, so now I have just a few questions of clarification:

1) when you (dibl) say "It's [installing the 64-bit packages I need] all automatic" do you mean that I can upgrade/replace 32-bit Kubuntu with 64-bit Kubuntu and the installer/new installation will automatically detect my previous packages and install 64-bit versions of them for me?

2) When you (dibl) say "there is no impact on your data files" do you mean that a 64-bit upgrade/replacement would not touch my Home directory or any of my desktop/KDE customizations?

3) How exactly do you (Grey) backup and restore your files and configs? Is it only necessary to backup the Home directory or are there config settings hidden in the system somewhere that requires specialized backup software to extract and restore?

And thank you both very much for helping me out here

[wizard10000]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

The technical answer is that most of your packages won't migrate from 32- to 64-bit so there's no reason to "back them up" - but here's whatcha do.

First, use dpkg to dump a list of the packages you have installed now plus any ones that came with Kubuntu that you uninstalled like this -

dpkg --get-selections > ~/Documents/installed-programs.txt

Then if your home directory's on its own partition you leave it alone (assuming you've got a good backup) - if it's not you back up your home directory and ideally restore it to its own partition before you do the new install.

I also back up /etc because it's got some systemwide settings I like to keep like grub configuration, the system crontab, NFS exports and other stuff like that. Don't restore all of /etc, just keep it for a bit so you can replace the files you need.

Then, install your shiny new 64-bit OS. Assuming the installed-programs.txt is the same place you left it in your home directory now you do this -

sudo dpkg --set-selections < ~/Documents/installed-programs.txt

which will load the list of programs you had installed before, and then

sudo apt-get dselect-upgrade

will install all the programs for you and remove any that you had removed on your old installation.

I run one of those dpkg dumps nightly as a cron job and it saved my bacon yesterday when a little bit of apt weirdness removed most of KDE. Using the procedure above I was back up and running in ten minutes

Good luck!

[dibl]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

Right -- what wizard10000 said.

1) when you (dibl) say "It's [installing the 64-bit packages I need] all automatic" do you mean that I can upgrade/replace 32-bit Kubuntu with 64-bit Kubuntu and the installer/new installation will automatically detect my previous packages and install 64-bit versions of them for me?

No, there is not going to be any awareness in the new OS of the packages you used to have installed in your old OS. Your new OS will replace your old OS, and everything in it. You are going to have to take care of replacing the installed packages, following wizard's method, or else by simply installing your desired packages one at a time.

2) When you (dibl) say "there is no impact on your data files" do you mean that a 64-bit upgrade/replacement would not touch my Home directory or any of my desktop/KDE customizations?

Yikes! Let me try again. "The new 64-bit OS will not do anything to/with your data that would not be done if you were installing a new 32-bit OS on your computer". So, if your /home directory is on the same partition as the rest of your OS, and you install a new OS on it, then your data will be wiped out along with everything else on that partition. Conversely, if your /home directory is on a separate partition, and during the installation of your new OS you select that partition to be mounted as "/home", then your data and your prior settings will all be preserved as-is (for better or worse).

I hope that is clearer -- if not, please ask again.

[Snowhog]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

Conversely, if your /home directory is on a separate partition, and during the installation of your new OS you select that partition to be mounted as "/home", then your data and your prior settings will all be preserved as-is (for better or worse).

As long as you don't tell the installer to format the /home partition. If you do that, all bets are off. :P

[The Woozy Fieldmouse]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

Lol, I didn't think I could be right about the 64-bit os automatically updating and so forth. I mean, Windows fails in many ways, but it can't be that far behind the curve. Thanks for the clarification muchly.

And Wizard, wow, man, you're a game-changer! I will be on those directions asap, and we'll see how it goes.

As for making a separate /home partition, I'm sold, but am not sure on how much space is good. The minimum https://help.ubuntu.com/community/Installation/SystemRequirements"]Ubuntu system reqs[/url] say 5GB for the core system. Is that right?

[Snowhog]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

As for making a separate /home partition, I'm sold, but am not sure on how much space is good. The minimum https://help.ubuntu.com/community/Installation/SystemRequirements"]Ubuntu system reqs[/url] say 5GB for the core system. Is that right?

Depends totally on how much HDD space you have available. I started using 8GB for my root partitions, and 25GB for my /home partitions. I find that 25GB /home partitions is more than I need, but given that my HDD is 120GB, partitioning it for three Kubuntu OS installs, allows me to create three 10GB root partitions and three 25GB /home partitions, with a 2GB swap partition, leaving a small(ish) unused space at the end.

[dibl]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

Excluding user data, you need 6GB as a minimum.

I would advise -- make it 15GB, and include /home in the partition where you install the OS. That way you'll have lots of space to download ISO images and such. You can use symlinks to link your data into the /home folder.

[Snowhog]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

I've found (so far) that 10GB for a root partition more than sufficient. But, I also only keep two kernels installed - when a third comes down, I delete the oldest one - and that keeps my space usage on the root partition well within the 10GB that I've established.

[kapil]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

i give 20 gb for root + home, (i.e. i mount / on 20gb space) comes handy when using the virtual box.

[The Woozy Fieldmouse]

Re: Best way to migrate to from 32-bit Kubuntu to 64-bit Kubuntu

Isn't there a way to keep the Home Directory on a separate partition and just make the new install use the old Home Directory?