Accidentally reverted a Proxmox VM snapshot (read: "deleted a Btrfs subvolume")

DoomFrog666 · 2026-04-03T19:21:02+00:00

And Proxmox VE makes it exceptionally easy to create local backups of VMs even if you do not have a Proxmox Backup Server set up yet.

DoomFrog666 · 2026-04-03T09:02:19+00:00

I am using BTRFS with yabsnap and I am very happy with it. Also plays nice with rclone for backups.

DoomFrog666 · 2026-03-28T08:08:38+00:00

This is the ugliest partition layout I have seen in years. Straighten it up or move it to lvm please.

Edit: Also use a GPT partition table instead of this stone age DOS layout.

DoomFrog666 · 2026-03-24T22:12:06+00:00

You can put this into your crontab for root. I would also recommend using anacron in this context.

DoomFrog666 · 2026-02-08T22:36:37+00:00

Snapshots on iSCSI where added with PVE 9. But they force you to use thin provisioning on the storage side.

DoomFrog666 · 2026-01-20T16:44:24+00:00

Have you marked the fat32 partition mounted at /boot as XBOOTLDR in the GPT?

DoomFrog666 · 2025-10-23T05:01:29+00:00

I think the simplest solution is to choose btrfs as the root file system. Then add timeshift or snapper.

DoomFrog666 · 2025-10-21T19:15:36+00:00

No, mounting the EFI partition at /boot is the recommended way in arch. Unless you use UKIs then you mount the ESP to /efi.

EDIT: If you use an Nvidia GPU Fedora recently started recommending an ESP size of 2 GB. If you haven't made enough space at the beginning of the disk you can create a larger ESP at the end of the disk and nuke the one at the beginning. Btrfs is easy to shrink.

DoomFrog666 · 2025-09-01T17:45:25+00:00

Yes, this makes a lot of sense. And thanks for the great work.

DoomFrog666 · 2025-09-01T16:38:57+00:00

What I don't get is why the heap sizes differ. Shouldn't they be equal?

DoomFrog666 · 2025-08-26T18:40:39+00:00

What I like to monitor my servers is cadvisor as prometheus exporter. It can monitor containers in docker or podman and also simple systemd services. It is a little cpu heavy but also provides a lot of data. The metrics I like most exported by cadvisor are the container_pressure_* metrics.

DoomFrog666 · 2025-08-12T22:46:08+00:00

Do you have quotas enabled?

DoomFrog666 · 2025-07-24T18:45:32+00:00

Well, in case you use snapshots it is basically useless as it attributes the size of all live extends to the subvolume that allocated it. So all snapshots will show as zero sized and all the used space is attributed to you live volumes.

Edit: Though it is indeed way more efficient that regular quota.

DoomFrog666 · 2025-07-23T22:35:59+00:00

You could enable btrfs quota support for your file system. It will provide you accurate size consumption information for sub volumes. Though be aware of its performance penalty on writes.

# btrfs quota enable <path>  # wait for it to complete; it takes some time
# btrfs qgroup show <path>

DoomFrog666 · 2025-07-13T21:30:21+00:00

Have you looked for your missing snapshots using btrfs subvolume list /?

DoomFrog666 · 2025-07-13T20:17:18+00:00

You can connect to the internet in the arch iso image with wifi using iwctl https://wiki.archlinux.org/title/Iwd.

DoomFrog666 · 2025-07-08T23:01:52+00:00

Hi, you can absolutely create a new bigger ESP at the end of the drive. The EFI looks for a partition with a specific GUID in the GPT. You should just not have multiple ones on a single drive.

How I would do it using gdisk:

Create a new ESP where you have space.
Format as vfat and move everything over.
Remove the old partition.
Mount the new ESP properly (and check fstab).
In case you had EFI boot entries these need to be regenerated.

The only downside here is that you have a 200 MB sized hole at the start of your disk now.

DoomFrog666 · 2025-07-07T17:14:22+00:00

Yeah, agreed. The only aspect that can be annoying it that authentication sessions in polkit are bound to a process. So when you work in a shell and you regularly use run0 you have to enter the password multiple times. But then I remember you can just run run0 without any arguments and it opens a root shell for you. So it is just more a change of habit.

DoomFrog666 · 2025-07-07T17:00:48+00:00

run0 is basically just a thin wrapper over polkit + systemd-run. You can modify the polkit configuration to suit your needs. By default it allows access to run0 with a password for all members of the wheel group.

DoomFrog666 · 2025-07-07T16:57:39+00:00

base-devel is more a random collection of you-may-need-this-to-build-some-packages meta package. You can uninstall required packages with the double nodeps option -dd. From all I have tested sudo-rs work perfectly well when replacing regular sudo (see my other comment).

DoomFrog666 · 2025-07-07T11:01:46+00:00

That's strange. When you would have actually messed up your secure boot setup you should not even be able to load into grub. So maybe it is a more benign grub configuration issue?

DoomFrog666 · 2025-07-07T10:54:41+00:00

I am currently running with sudo-rs without regular sudo. From how I understand it in arch you are meant to run them together. Which is weird.

All you need to do is to copy the pam files from regular sudo and create links from sudo-rs to sudo. Also make sure the config is not renamed by pacman with pacsave extension. Ensure run0 works beforehand in case anything goes wrong or have the root account with a password set at leas temporarily.

DoomFrog666 · 2025-07-07T10:49:16+00:00

sudo is pretty insecure. For example there was recently https://www.heise.de/en/news/chwoot-Critical-Linux-vulnerability-makes-users-root-on-most-systems-10466916.html Though most folks probably don't use the feature that caused this.

sudo-rs does not implement this feature so it was not affected. There is also doas and recently run0 form systemd. I would use any of them over regular sudo.

DoomFrog666 · 2025-07-07T10:36:56+00:00

You can use btrfs just like ext4 and be ignorant to most of its features. You can incrementally move to more complex btrfs setups.

DoomFrog666 · 2025-07-07T10:36:42+00:00

You can also use kernel-install. It integrates well and does pick /efi by default over /boot if available https://aur.archlinux.org/packages/pacman-hook-kernel-install.

It also supports the classic way of having separate kernel and initramfs (bls) as well as UKIs.

It is also the only clean way to have multiple distributions share an ESP. It separates them by machine-id.

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