Encrypted Manjaro over SSD and HDD with LVM cache

I am trying to install a fairly complex setup. My idea is very similar to this setup but i am not sure I understand the best possible way to do it in Manjaro.

My idea is to follow the partition, lvm and luks steps in the article manually and then switch to Manjaro Architect. When selecting mount points in Manjaro Architect I am not sure how to select. For / I understand that I should select /dev/mapper/root, but there are multiple entries for /dev/mapper/root in the test environment I am experimenting with. Does it matter which one do I choose? In which way does the system configure RootVG/cryptroot to be mounted in /dev/mapper/root? Am I making the installation harder than it should be? After reading the Arch Wiki and one topic that was related in the forums I am not sure what do I have to do to integrate the manual steps with Manjaro Architect.

You shouldn't map over devices of different types.

Though I do not know if it is possible - I can imagine you would be in for some weird errors if you map across ssd and normal spinning drives.

The basics of LVM is that you map physical devices into one or more virtual devices.

You can make your virtual device span multiple physical devices and this is the point where if think combining ssds and spinning drives is a bad idea.

When you have a virtual device you divide that device into virtual partitions which you then use as destinations for your mountpoints.

Okay, so luks root on lvm that spans 2 devices, + swap on separate encrypted lvm... You could simplify it by dropping the swap specific lvm.

Why is it a bad idea?

My intention was to set up my system with full disk encryption, without having to introduce my password twice. When I read the article I link to in the original post I also thought that being able to make use of the extra speed of the SSD transparently was interesting. Is there a way to be able to do this? The only other option that comes to mind is the usage of a keyfile for one of the disks, but I do not see how best to design the layout to use the SSD's speed. The SSD as a cache, like in the article, sounds like a good option.

Also I wanted to learn how could I mix Manjaro-Architect with some steps being done from the cli, or if it is possible in a comfortable way.

And dropping the swap specific lvm what do I select in Manjaro-Architect for it to know where to install the OS? The problem that I am having is that when setting up luks+lvm from the cli I am not sure how to integrate that work to install everything with Manjaro-Architect.

Because of the performance - the last section of the mentioned post.

The cache will have to wait for the slower spinning driver which creates a bottle neck.

You can still try the setup but keep the system volume on ssd and link storage hungry folders to a volume on the hdd.

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Just put your root to the ssd and /home to hdd. Then use profile-sync-daemon to put your browser performance affecting files to ram.

Mount your root to /mnt and everything else under /mnt. That way manjaro-architect installs to the desired location.

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Ok. Thanks, I had not understood that part properly.

Ok. Thank you, I will do that.

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