I hope that my very scarce readership and their relatives and friends are well. These are going to be very trying times. It is because of this that spreading rumours and messages that aren’t contrasted has to be discouraged. Rumours kill people. Please, consult official and trusted sources of information.…
Ubuntu: Installing/fixing TP-Link AC1200 (T4UH 1.0) drivers in Ubuntu 20.04 LTS
I wrote an entry about this adapter and Ubuntu 18.04. This week my 20.04 LTS installation started to freeze randomly. I suspected several things, but through a process of elimination it ended up pointing to the Wi-Fi adapter. I can’t rule out a hardware issue yet, but the new driver…
macOS: Application stealing focus
A few weeks ago I had an issue with a macOS system which focus kept being stolen by an unknown application. All the windows were displaying as inactive so it had to be a background process. A StackExchange user called medmunds had adapted a script from another post, that seems…
VirtualBox/KVM: Reduce VM sizes
There are two utilities that can help discard unused blocks so that VMs can be shrunk. zerofree finds unused blocks with non-zero content in ext2, ext3 and ext4 filesystems and fills them with zeros. The volume can’ be mounted which makes the process of running it a bit convoluted. fstrim…
Ubuntu 20.4: Virtualbox not running after the last upgrade
When launching a VM in Virtualbox I got an error saying that it can’t be started because a required module isn’t loaded. It suggests to manually load it. Re-installing Virtualbox also fails because the virtualbox-dkms package can’t be configured The last system update upgraded the kernel from 5.4 to 5.8,…
Ubuntu: ZFS bpool is full and not running snapshots during apt updates
When running apt to update my system I kept seeing a message saying that bpool had less than 20% space free and that the automatic snapshotting would not run. What I didn’t realise is that this would apply to the rpool even if it had plenty of free space. They…
Ubuntu: System freezing for a few seconds with iwlwifi microcode sw error
For a few months now my main system would momentarily freeze or stall (usually about 20-30 seconds) and then continue working. It was something that started after one system update and wasn’t fixed with any further updates. I opened a bug with Debian without much luck. The system would notify…
Ubuntu/Linux: systemd-resolved[2344]: Server returned error NXDOMAIN, mitigating potential DNS violation DVE-2018-0001, retrying transaction with reduced feature level UDP.
In one of my systems the system log was reporting every 2-3 minutes the following error message: This was caused by a mismatch between the systemd configuration and /etc/resolv.conf. /etc/resolv.conf should be a symbolic link pointing to the systemd DNS configuration in /run/systemd/resolve/resolv.conf You can check if this is in…
Ubuntu/GRUB: Error: invalid environment block
After a recent system update I got the following error message: Luckily the system would boot up but ignoring errors isn’t best practice. This error is caused by a faulty GRUB2 environment block. This is a file located in /boot/grub/grubenv. You can easily regenerate it with the following commands. It…
Ubuntu 20.04: Install Ubuntu with ZFS and encryption
Ubuntu 20.04 offers installing ZFS as the default filesystem. This has lots of advantages. My favourite is being able to revert the system and home partitions (simultaneously or individually) to a previous state through the boot menu. One major drawback for me is the lack of an option to encrypt…
Ubuntu: Ubuntu 20.4 installing NVIDIA drivers breaks built-in audio on laptop
On a new laptop I couldn’t get the external HDMI monitor to work with the nouveau drivers, so I installed the NVIDIA drivers (version 440). The NVIDIA drivers worked perfectly and the external monitor could be configured, but it didn’t take too long to notice that the built-in audio wasn’t…