Nextcloud user and data tansfer after (somehow) corrupted database

18. February 2021 - Reading time: 14 minutes

I run a Nextcloud instance since Nextcloud 10 came out, which means since somewhen 2016. Initially, this instance was used for file sharing and syncing calenders and address books for me and my wife. During the years until today, both its range of tasks and the amount of active users grew up, and similarly its demand for compute power. As a consequence, this Nextcloud instance went not only through all major releases that came out. It was also transferred from a shared webspace hoster over a 1-core-4-GiB virtual server to the 2-core-8-GiB virtual server where it lives today, all without setting it up from scratch. So actually pretty impressive that this Nextcloud survived the transfers, the release upgrades and me messing around with everything on that server while... gathering experience with Linux ;-).
Even if the Nextcoud's services ran without (noticeable) failures, during the last months my error log filled up with database-related issues, especially after my MariaDB database died one day mysteriously and had to be restored from a two-day-ago backup (I point to the hoster and some file system problems, but this was never admitted). While I was able to solve some of the issues by e.g. changing manually data types, new issues popped up faster and faster (surpise ;-)). So, over time, the need to tackle the database problem properly and fundamentally grew. To do that as clean and straightforward as possible, I planned (and performed) to set up a fresh Nextcloud, while finding the best compromise between transferring as little as possible from the (corrupted) database and annoying my users as little as possible.

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How to prevent sleeping disks from spinning up at SSH login (Ubuntu 20.04)

17. August 2020 - Reading time: 2 minutes

My home server running Ubuntu 20.04 acts as a NAS besides several other roles. Most of the time (as long as no one is accessing data) the associated hard drives are sleeping, spun down by hd-idle after 10 minutes of inactivity. What annoys me really bad is that they spin up most of the times I only login to the server via SSH: Every spin-up wears out the drive and every unnecessary spin-up wears out the drive unnecessarily. Since all OS data is located on a SSD, none of the NAS hard drives should be touched during SSH login. After some internet research I found the reason for this behavior and a solution that is working for me: Read more

Backup stuff - rsync requires special invitation to handle hard links right

5. May 2020 - Reading time: 2 minutes

Desiring to be prepared for a hard disk drive failure in home server applications like NAS often leads to some kind of RAID setups. Since I want to balance data security versus energy consumption, my current compromise according to that is to avoid a RAID (too many disks spin up if I only want to access one file), but to sync the primary hard drives once a week to secondary hard drives. Read more

Fingerprint registriation fails - resetting all fingerprints in Android 9.0 / LineageOS 16.0

2. January 2020 - Reading time: 2 minutes

OK, that's definitely more a reminder for myself, but maybe some visitor has the same problem: After doing nothing recognizable on a Sony Xperia XA2 all previously registered fingerprints seemed to be deleted and the registration of new ones failed every time with an error message (something like "registration failed, please try again or use another finger"). Read more

Using Eduroam or any other kind of WiFi that requires TLS authentication on LineageOS

15. December 2019 - Reading time: 4 minutes

I'm using LineageOS since several years and on various devices and maintaining some of them for family and friends. There, on two different kinds of phones (Samsung Galaxy J7 and Sony Xperia XA2) and on two different universities in Germany the issue popped up that they're not able to connect to the university's WLAN network Eduroam. The network's SSID is shown in the phone's WLAN settings, but they're not able to connect, even if they follow the network connection guides provided by their university, respectively. I was not able to reproduce this behavior on my home university, there everything works perfectly.

After some research (e.g. here and here) I found the reason and some kind of solution / workaround:

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Initial Post

4. December 2019 - Reading time: 2 minutes

Hello Internet!

After years of having a bunch of domains, first playing around and later using productive some great tools like Nextcloud, Wordpress, Prosody, Mumble or Wireguard and having also the standard stuff like LAMP, Mail (Postfix / Dovecot), Samba, CUPS and so on running on Debian, partly within the powerful KeyHelp environment, I felt the lack of having something like a landing page with an overview over all services and possibilities my servers are currently offering. As you can see that's available hereby and as you can see as well, it's still some free space on this site. I'll use that space for some blogging that will most likely focus on the tech and infrastructure stuff I've outlined above - partly, to give some help or useful hints for anyone coming over from anywhere, partly to just have a well-structured documentation for myself ;-). Stay tuned...