Applied technology, resilience, survival, photography and Mate
When going through my picture collections, I've compiled the latest Best-of-iceland picture collection. Most of them are also on Unsplash and in my picture album, but some of them are only here. Enjoy!
Neuschwanstein castle - It's really like in a fairytale. I'll just leave this here
Another new bread recipe, that I'm right now working on. From the same book as the last experiments, and because of copyright reasons, I won't put the recipe here (Get the book!)
I am very happy that the bread didn't glued too much. In the meantime the kitchen smells amazing, and I can't wait for tomorrow morning to try out this beauty.
For now, good night.
Refreshingly simple recipe with a strong taste. Consider adding fresh peppermint and a lime
Peel and cut the Ginger into stripes. Put the Ginger into the water, add the juice of the lemons and cook for 5 minutes. Still in the hot pan, blend it using a hand blender. Then add the sugar and cook it for another 5 minutes.
Put into bottles. Recommended to use within half of a year.
This blog post is about getting Kodi up and running with Netflix on Raspbian. This is not a tutorial, more a collection of notes for myself in order to reproduce the setup.
Get a recent version of Raspbian from the Raspberry Pi website. (Or my ftp mirror). Extract it to a fresh micro-SD card and get the system ready. Follow this guide, if you need help. Boot into the system and run a update and install some handy tools
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sudo apt update sudo apt upgrade sudo apt install git tmux screen htop iftop iotop useradd kodi usermod -aG audio,video kodi |
Next, we are gonna harden the system. For that do the following
First add the following repository
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# editor /etc/apt/sources.list.d/pipplware_unstable.list deb http://pipplware.pplware.pt/pipplware/dists/unstable/main/binary / |
Now install kodi
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sudo apt install kodi |
Ok, kodi is installed, now we need to start kodi. For that we create a systemd service by putting the following to /etc/systemd/system/kodi.service
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[Unit] Description=Kodi standalone After=systemd-user-sessions.service network-online.target sound.target mysqld.service Requires=network-online.target Conflicts=getty@tty1.service [Service] User=kodi Group=kodi PAMName=login TTYPath=/dev/tty1 ExecStart=/usr/bin/kodi-standalone Restart=on-abort StandardInput=tty [Install] WantedBy=graphical.target |
The Netflix Plugin is hosted on GitHub. Download the plugin and install the zip-file. Best option seems to be to put it on a USB-Stick and install it from there. This plugin needs parted or fdisk, you install them on your kodi and then let the plugin install the widevine library, necessary for the DRM. The DRM is by the way also the thing, that was in the way of getting Netflix work in the first place. And it's still a bit of a mess, since we are using here a extraction of the libwidevine from the chromecast.
Well, as long as it works, but it's not nice and probably creating causing one or two times headache until it finally works.
This is now more a quick fix, based on the suggestion from here. The original clue was posted long time ago on the kodi forums, but those posts were only of limited help. So, create the following file
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# editor /etc/polkit-1/localauthority/50-local.d/all_users_shutdown_reboot.pkla [Allow all users to shutdown and reboot] Identity=unix-user:* Action=org.freedesktop.login1.*;org.freedesktop.upower.*;org.freedesktop.consolekit.system.* ResultActive=yes ResultAny=yes ResultInactive=yes |
I encountered the problem, that if Kodi runs for too long (multiple days), the Netflix plugin stopped working. No errors given, it just won't play a movie again. A quick fix is to schedule a reboot every night using a cronjob
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crontab -e # Reboot the system every night at 5am 0 5 * * * /sbin/shutdown -r now |
This is of course just the basic installation. You will need to configure Kodi to your needs (Skins, Addons, Timezone, connect your NAS, ...)
Also, I might create an ansible-playbook to setup this procedure. This looks like a fun project to do on a rainy Sunday.
For now, I'm off, watching some Netflix 🙂
Disclaimer: I don't want to blame anyone. I love btrfs and would very much like to get it running in a good manner. This is a documentation about a use case, where I have some issues
I am setting up a new server for our Telescope systems. The server acts as supervisor for a handful of virtual machines, that control the telescope, instruments and provide some small services such as a file server. More or less just very basic services, nothing fancy, nothing exotic.
The server has in total 8 HDD, configured as RAID6 connected via a Symbios Logic MegaRAID SAS-3 and I would like to setup btrfs on the disks, which turns out to be horribly slow. The decision for btrfs came from resilience considerations, especially regarding the possibility of creating snapshots and conveniently transferring them to another storage system. I am using OpenSuSE 15.0 LEAP, because I wanted a not too old Kernel and because OpenSuSE and btrfs should work nicely together (A small sidekick in the direction of RedHat to rethink their strategy of abandoning btrfs in the first place)
The whole project runs now into problems, because in comparison to xfs or ext4, btrfs performs horribly in this environment. And with horribly I mean a factor of 10 and more!
The results as text are listed below. Scroll to the end of the section
I use the tool dbench to measure IO throughput on the RAID. When comparing btrfs to ext4 or xfs I notice, the overall throughput is about a factor of 10 (!!) lower, as can be seen in the following figure:
sda1 and sda2 are obviosly the same disk and created with default parameters, as the following figure demonstrates
My first suspicion was, that maybe cow (copy-on-write) could be the reason for the performance issue. So I tried to disable cow by setting chattr +C and by remounting the filesystem with nodatacow. Both without any noticeable differences as shown in the next two figures
Hmmmm, looks like something's fishy with the filesystem. For completion I also wanted to swap /dev/sda1 and /dev/sda2 (in case something is wrong with the partition alignment) and for comparison also include ext4. So I reformatted /dev/sda1 with the btrfs system (was previously the xfs filesystem) and /dev/sda2 with ext4 (was previously the btrfs partition). The results stayed the same, although there are some minor differences between ext4 and xfs (not discussed here). The order of magnitude difference between btrfs and ext4/xfs remained
So, here are the results from the figures.
| /dev/sda1 - xfs | Throughput 7235.15 MB/sec 10 procs |
| /dev/sda2 - btrfs | Throughput 623.654 MB/sec 10 procs |
| /dev/sda2 - btrfs (chattr +C) | Throughput 609.842 MB/sec 10 procs |
| /dev/sda2 - btrfs (nodatacow) | Throughput 606.169 MB/sec 10 procs |
| /dev/sda1 - btrfs | Throughput 636.441 MB/sec 10 procs |
| /dev/sda2 - ext4 | Throughput 7130.93 MB/sec 10 procs |
And here is the also the text file of the detailed initial test series. In the beginning I said something like a factor of 10 and more. This relates to the results in the text field. When setting dbench to use synchronous IO operations, btrfs gets even worse.
Phoronix did a comparison between btrfs, ext4, f2fs and xfs on Linux 4.12, Linux 4.13 and Linux 4.14 that also revealed differences between the filesystems of varying magnitude.
As far as I can interpret their results, they stay rather inconclusive. Sequential reads perform fastest on btrfs, while sequential writes apperently are horrible (Factor 4.3 difference).
(Sorry, it's in German) (Sorry again, ich bin wütend)
In Anbetracht des aktuellen politischen Klimas: Woher kommt denn nochmals die ganze Politikverdrossenheit? Warum nochmals fühlen sich vor allem jüngere Wähler nicht oder nicht mehr repräsentiert?
PS. Das Outcome der Entscheidung zum Uploadfilter ist hier vollkommen belanglos. Wir können einen Kampf führen und wir können auch verlieren. No hard feelings about that.
Aber WIE in den letzten Wochen mit Kritik umgegangen, wie von seitens einiger EU Parlamentarier bewusst diffamiert und beschwichtigt wurde, ist inakzeptabel.
Das werden wir nicht vergessen. Wir sehen uns bei den nächsten Wahlen.
I just found a new book to work with: "Brotbackbuch Nr. 1" from Lutz Geißler (in German) and love it from the beginning. Every recipe is listed with the effective and absolute time it needs, and apart from the recipies it also incorporates a lot of background informations and craftsmanship knowledge. I came to this book via the (also German) podcast Chaosradio Express, or more specifically, episode 213 - "Brot".
But enough waffle.
My latest creation is the most basic recipe from the book: The "Landbrot"
The recipe is very basic but because I cannot find it publicly at brotbackbuch.de I have to assume it's under copyright. Still some notes about making this bread
Yeah, I am running a recent self-made build of Linux 5.0 🙂
Despite the major version number change, there's nothing more special about this version, that with other releases. Still, I find this pretty cool!
Now, back to work ...
This is just a short note to remind me, how to configure a link-local IPv6 address in the ssh-config
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~/.ssh/config<br>HOST raspberry USER pi HOSTNAME fe80::0001%%eth0 AddressFamily inet6 |
Remember to put two precent signs, otherwise you might get errors similar to the following
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percent_expand: unknown key %e percent_expand: unknown key %w percent_expand: unknown key %t |
IPv6 for the win!