From time to time, when I upgrade my standalone Unifi controller (running in FreeBSD jail), I run into an issue which requires some manual action to resolve. The issue manifests as MongoDB (bundled with Unifi controller) refusing to start with existing data. Checking logs (/usr/local/share/java/unifi/logs/mongod.log) I can see the following (this log file is in JSON format - not particularly friendly for humans but still readable):

{"t":{"$date":"2025-02-01T21:39:17.097+00:00"},"s":"F",  "c":"CONTROL",  "id":20573,   "ctx":"initandlisten","msg":"Wrong mongod version","attr":{"error":"UPGRADE PROBLEM: Found an invalid featureCompatibilityVersion document (ERROR: Location4926900: Invalid featureCompatibilityVersion document in admin.system.version: { _id: \"featureCompatibilityVersion\", version: \"4.4\" }. See https://docs.mongodb.com/master/release-notes/5.0-compatibility/#feature-compatibility. :: caused by :: Invalid feature compatibility version value, expected '5.0' or '5.3' or '6.0. See https://docs.mongodb.com/master/release-notes/5.0-compatibility/#feature-compatibility.). If the current featureCompatibilityVersion is below 5.0, see the documentation on upgrading at https://docs.mongodb.com/master/release-notes/5.0/#upgrade-procedures."}}

I'm not very experienced with MongoDB and this message looks rather obscure and scary. Fortunately so far it was fairly easy to fix.

Writing this mostly as a reference for myself should I run into this problem in the future.

Pasting into vim running under tmux was producing weird results. For example pasting wiwiw would actually produce Wiw.

I had a chance to try Zigbee extension lead sold by Lidl under SilverCrest brand.

Browsing the list of ESPHome components I noticed a picture that looked very familiar. In my house I have this device branded as "Joule" and labeled "DeltaSolⓇ BS HE" and on ESPHome site they show "Resol DeltaSolⓇ BS Plus":

This topic is generally well documented in the relevant part of the FreeBSD Handbook Chapter 12. Except for a small detail which becomes important in certain configurations.

I was recently installing Arch Linux in a VM following my own notes which are a simplified and shortened version of official instructions. The same procedure clearly worked approximately 6 months ago but for some unknown reason now the new system would not boot and would instead drop into Grub prompt. It turned out that Grub was not able to read ext4 filesystem produced with the recent mkfs.ext4 command.

For a while I wanted to restart my blog and this is what I'm doing now.