Is it possible to install Silverblue on SSD without reformating

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1

I have a large 2 TB SSD with

/dev/sda1 700MiB
/dev/sda2 1400MiB
/dev/sda3 LUKS/BTRFS

Is it possible to install Silverblue on that disk without recreating the LUKS/Btrfs part? If yes it would save me to restore a lot of data after having installed Silverblue.

2

Hi and welcome to :fedora: !

What flavor of Fedora did you have installed before? If it was Silverblue, is there a reason you need to reinstall it?

If it’s the home subvolume that you wouldn’t want overwritten, I guess you could take a snapshot and copy it temporarily to another disk with btrfs send | receive (see this Fedora Magazine article for details), then perform the installation with custom partitioning, by choosing the existing partitions. The partition contents will be overwritten though, so you’ll need to restore the snapshot of the home subvolume.

The process could be tedious, so make sure you have other backup means in place as well.

3

Actually it is a bit more complicated. :grin:

Coming from a non immutable distro I actually want to install Aurora. However, my understanding is that the capability of the installer is pretty much the same for Fedora Silverblue, Aurora, Bluefin or whatever.

I know how to deal with a situation where I have to deal with backup or as you suggest using btrfs send/receive. Actually, we are talking about 10 btrfs subvols to either send/receive or to restore.

That’s why I was hoping I can persuade the installer to be good to me. I did some testing and the installer stepped into my a.. :laughing:

From what you tell me I take that currently the installer is not able to do it my way…

4

I’ve installed Silverblue several times, both with automatic and custom partitioning, never using Blivet-GUI though. I don’t remember exactly, but I was assuming that the partitions would be erased with custom partitioning too. I might be wrong, and maybe the installer works on subvolume level.

It’s worth playing around with the installer, without actually starting the installation, maybe it’s suggestive enough to tell you whether partitions will be erased or only subvolumes.

5

This thread discusses the case where you retain a BTRFS partition and overwrite one subvolume (typically /) while retaining others (typically /home). It refers to this as “Goal A”

This refers to the “old-style” Anaconda installer. I think the atomics are still using this, as is every flavour of Fedora except for F42 Workstation.

It doesn’t mention encryption explicitly, so I’m not sure whether LUKS complicates things.

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7

Playing around with the installer I came to the same conclusion, i.e. without erasing the partition no installation will happen.

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8

Hm, yes. If I understand this correctly it also shows that there is no chance.

9

As far as I can see, there are two viable ways it can be done - “Option A1” using custom configuration, or “Option A2” using blivet-gui.

10

I tried both and the installer always came up with warnings and I could not start the installation.

11

I got it working… :joy:

Reading the information twice (I am a bad reader…) @pg-tips gave me I understood.

Very important: the subvols root, var and home must not exist.

Here what I did

Going directly into the blivet gui and …

  • choosing /dev/sda1 for /boot/efi
  • then /dev/sda2 for /boot and here it is important to say formatting as ext4
  • now unlocking the btrfs volume
  • with the + button add a new subvolume root with mount point /
  • then add a new subvol var with mount point /var
  • finally add a new subvol home with mount point /var/home

and then the installer is happy because it can create those subvols.

I could run the installation and then I booted into the newly installed system and the “old” subvols were still existing.

I am very happy now as this is how it should be. :laughing: :laughing: :laughing:

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12

Basically this confirms that in case of BTRFS the installer creates new subvolumes, but doesn’t touch the non-predefined existing ones.

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13

Switch to Aurora from an Arch based Linux was succesful.

I discovered that the installer wanted me to mark the /dev/sda1 as bootable. Otherwise, it complained. Then the blivet gui identified the partition as EFI and the iinstallation went fine without any accident.

Fortunately, I had been using “normal” Fedora for years privately and in my company. This helped me a lot because…

I got some permission errors (regarding to my data coming from previous Linux which of course was context-less) and in my mind the word SELinux popped up and shortly later the word restorecon appeared. Then I knew what to do to make me happy. :rofl: