And to emphasize this: nothing of this operates on the VFS level, it operates on the btrfs level and block level instead. Copying in files and directories is 1990s shit. Not how a modern image based OSes should work.
Once you want to migrate to the internal disk, we just tell btrfs to swap out the backing device of the btrfs, from the zram device to a block device backed by the internal disk. (and we also tell dm-verity to switch is backing of /usr/ too, once we copied it over).
That's really all there is.
During the entire runtime there's only a single btrfs file system, it just has initially one backing device, then two (while streaming over), and then one again.
@agowa338 @gwen i don't understand where the confusion is, but generally, in modern immutable OSes one tries to separate mutable state from immutable OS resources. The former sits in a file system such as btrfs. The latter in a verity protected erofs or so. When booting a fresh instance you take the erofs, mount it to /usr/ into an empty btrfs, and boot up. In the live installer case, that btrfs can be backed by zram. So you will have the mutable part of the OS run off RAM, and the immutable…
Cum să cureți caserolele din plastic îngălbenite folosind ingrediente din bucătărie - Oțetul alb dizolvă petele galbene din recipientele de plastic. Toarnă oțet și apă în proporții egale până acoperă zona îngălbenită. Lasă caserola la înmuiat peste noapte. A doua zi, clătește bine. Oțetul elimină pigmentii și readuce plasticului culoarea originală.
I think that you hit the nail on the head there. You offer up a wonderful buffet. A smorgasbord of delights.
The fact that some prefer to nibble solely on your baps, eschewing everything else, means everyone can enjoy what you do, in a way that works for them.
(And I *do* enjoy what you write, even if I am a plaintext using heathen.)
@flotmjor938382 Hey! So our team has said that our rss feed contains title, description/summary and the post url.
If you use a feed reader that is constrained to the actual rss content, then this is all you will see. Many (most?) rss readers we know can follow the post url and fetch the full post on demand. Some can do it automatically.
@agowa338 no, why would it? it's an in-memory file system, it does not persist across reboots or between systems. The btrfs on it is freshly formatted after the zram device is allocated.
@agowa338 btrfs device replacement is a btrfs native feature. It knows how to invalidate the old device to avoid identifier clashes. And the old device only existed in RAM anyway (i.e. backed by zram0), so once that device is destroyed there's no trace kept around that the backing device of the btrfs fs once upon a time wasn't the internal hard disk.
…to a target block device, without ever being unmounted. It uses the device replication feature of btrfs for this, so that this is reasonably robust.
How would one use that? The idea is that the USB live media carries an immutable /usr/ which when booted sets up a zram device for the rootfs, formats it as btrfs, where /usr/ is then mounted into. systemd-repart can then be used to duplicate /usr/ (and its verity + sig data) onto the target disk, and then sets up a root fs (+ encrypt it), and…
…to just boot up from your USB stick, and use it for a while in "live" mode. Then, after liking it you decide to actually want to install it on the built-in hard disk. So what if we could start the install process now, that just migrates the running OS without a reboot into the built-in hard disk. With v261 systemd will provide tooling for this: systemd-repart learned a new option BlockDeviceReplace=. If used it can "migrate" a running and mounted btrfs file system from a source block device…
…mode of operation it is typically used to stream in a /usr/ OS tree onto a suitable partition on the target disk, and then creating a new root fs on it too (either from the installer, or even better after rebooting into the freshly installed OS) That's very efficient and robust, hence seems like it's the ideal way to install an OS, no?
As it turns out one can do it even better: rebooting sucks of course. How about an installer where you do not even have to reboot? You might want…
1️⃣5️⃣ Here's the 15th post highlighting key new features of the upcoming v261 release of systemd. #systemd261 #systemd
In a previous episode of this series we already talked a lot about installing operating systems, and the new features systemd v261 brings for that. There's one more item in this area I'd like to talk about:
You know systemd-repart is that dynamic partitioner that can also be used for building disk images and as an installer for image-based operating systems. In the latter…
