What is the Silverblue installation recommendation with 2 internal drives?

My personal computer is a Dell 27 7775 AIO with a 256GB NVMe drive, and a 1TB HDD built in (currently running Debian 11 testing). I have been trying out Silverblue on a laptop and I now would like to do a clean install on my personal computer.
I know the documentation for Silverblue recommends Automatic partitioning, but have also come across guidance that suggests this is not recommended with btrfs across the 2 drives (though I have not come across why, or what the problem with that would be).

So, my questions are, 1. Would I be ok letting the automatic partitioner do its thing? or
2. If not, what would the recommended configuration be (and how to achieve that)?

-I’m not new to Linux (low-moderate experience), but I am new to btrfs

Thanks for any guidance/advice you can provide!

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There are two parts here… “What is the recommended configuration?”, and “How do you achieve that?”. I’ll give my opinion on both.

What is the recommended configuration?

For performance reasons the HDD will not be great for day-to-day general usage. I would suggest that you plan to use the NVMe “by default”, and punt only specific things to the HDD where you don’t mind the performance drop or you simply don’t have the NVMe capacity.

Think about what data you have that you don’t need fast access to. Media collections or backups might be a good candidate here, and consider moving only those to the HDD.

It would not be worth having both drives in the same btrfs filesystem, as the performance and capacity disparities will lead to the worst of both worlds. You either enable “raid1” profile and then are limited to the capacity of the smaller drive, or you enable “single” profile and btrfs will fill the “emptiest” disk first (ie the HDD) leading to poor performance. Instead, create seaparate filesystems on your drives and treat them separately.

How do you achieve that?

One option is to just ignore the HDD during installation. Point the automatic partitioner at the NVMe drive only, and let it do what it wants. Once your installation is working you can partition and mount the HDD as you wish.

I have a machine with NVMe + HDD and did effectively this. I consider myself experienced with Linux, but not experienced with Fedora or its installer. For me this was a reasonable approach.

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Thank you, Paul! That’s very helpful, and basically how my current Debian install is configured (with just /home on the HDD), although ext4, not btrfs.
This raises a couple more questions for me, though. If I ignore the HDD on the Silverblue automatic install to NVMe drive only (btrfs), and mount the HDD after the fact, could/should I leave that in it’s current ext4 state? Is there anything further I need to do to make the whole system play nicely together?
John

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That’s very helpful, and basically how my current Debian install is configured (with just /home on the HDD)

I would recommend putting your home directory on the NVMe too. Things like browser profiles, application config, caches, and so on will all benefit from being on the faster drive and make your system feel snappier. When I suggest using the NVMe “by default”, I mean it. :slight_smile: Consider putting only your large archives, backups, or media collections on the HDD.

On my system I mounted the HDD someplace like /var/archive_storage. I then made ~/Photos and ~/Downloads be symlinks to directories on the HDD mount.

could/should I leave that in it’s current ext4 state?

ext4 is extremely well supported. It was the default in Fedora until quite recently (Fedora 33 - Oct 2020), and remains the default in many other distros. You may consider reformatting to btrfs if you imagine taking advantage of the extra features it provides like transparent compression, snapshots, bitrot detection.

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Thank you again, Paul. I very much appreciate your time and guidance.
I think I will plan to leave the HDD as ext4 for simplicity’s sake (at least until I am more familiar with btrfs). Can you confirm that there are not any issues/conflicts with having one drive btrfs and the other ext4?
Hoping to have some time this weekend to give it a go, and looking forward to it!

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Can you confirm that there are not any issues/conflicts with having one drive btrfs and the other ext4?

None that I am aware of. I think mine has ext4 for /boot and btrfs for everything else, for example. This will be very common.

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