usb key replicate

* usb key duplicate

* partition table

  manual cgdisk

* rsync partitions

  rsync -auv --progress <source></source> <target>

* rsync caveat : hard links, sparse file

  warning: some sparse files may have huge virtual size
    rsync, will attempt to expand them fully
    i.e: docker devicemapper (60MB on disk, virtually 100G)

  warning: some programs have one fat binary with hard links
    rsync, will attempt to copy them fully
    i.e: git, which has 114 hard links with different names

* BIOS boot (ef02) partition

  dd if=/dev/sdX1 of=/dev/sdY1 bs=1M # simply

* grub

  sudo grub-install --target=i386-pc --debug --boot-directory=/<root-mountpoint>/boot/ /dev/sdY

  warning: do not mess the device names and mountpoint names as it may modify your host system grub config


* grub UUID

  grub menuentry refers to source key UUID

* adjust root UUIDs
  /etc/fstab still refers to source key UUID

  blkid /dev/sdX? &gt;&gt; /etc/fstab
  vi /etc/fstab

  (some sed-fu would be nice)</root-mountpoint></target>

nixos 16.03 live iso boot "directly" from grub

I hate extracting iso images. I prefer to run them through grub loopback. Nixos 16.03 release is a few days old, I couldn't resist. Alas, booting it this way drops me in a rescue shell.

The initrd is set up to only have one layer of virtual fs. So it assumes the squashfs nix-store would be in /mnt-root/iso and complains since it is not.

So after trying to MITM myself and mount the desired FS where they should be, I replicate the final steps of the nixos initrd init script. Kernel panic.

I'm dumbfounded, I need to be more thorough. The init scripts reads a fsinfo file (fstab-like in a different format say) to prepare the new root for the real stage 2 kernel.

btw, my mistake was to simply mount the nix-store squashfs file in /mnt-root/nix/.ro-store and then symlink /mnt-root/nix/store to it. It works only partially as the stage2 kernel find its init and proceed to run systemd but hangs after a few services doing nothing. Only option: CTRL-ALT-DEL. (I even tried to instrument stage2 systemd into booting the rescue target, hoping for a rescue shell to investigate the hang .. no luck). Then I realize that the fsinfo mounts the squashfs in nix/.ro-store BUT, also prepares a unionfs in nix/store ! Maybe stage2 is waiting for a unionfs mount in nix/store and my symlink is confusing things up.

So I insert the missing layer in there. And just sh /init. It fails horribly saying 'cannot stop udev/queue' then 'Killed'. Not thrilled.

I extract the final steps of the init script (populate /mnt-root with proc,sys,run,dev; kill a few things; restore the path for `modprobe` in the new /proc/sys/kernel/modprobe value). And then exec switch_root ...

I can now enjoy nixos 16.03 live booting directly from grub. If you allow directly to allow user intervention .. heh.

DELL 4500s from the forest - chapter 3 : the install-partying

So that old DELL 4500s runs. I also found an recent (using systemd) archlinux live cd so I can enjoy a more modern driver set and OS utils. But it can't boot usb, so I'll have to find another persistant storage device, namely : a hard drive. No problem, I have a dozen hard drive sleeping under my bed. Except half of them are < 4G or SATA, all but one [ex IBM] Hitachi Deskstar 80GB (you know, the model just after the Hitachi DeathStar 60GB failure generators). One empty slot in the partition table, 7GB+ of capacity, perfect. That doesn't solve the boot issue, I don't have a spare partition for grub. I'll try to bootstrap the boot from the live cd. I'm in the mood for some serious bad idea attempts tonight.