TOPIC: UNIVERSALLY UNIQUE IDENTIFIER
Changing the UUID of a VirtualBox Virtual Disk Image in Linux
11th July 2021Recent experimentation centring around getting my hands on a test version of Windows 11 had me duplicating virtual machines and virtual disk images, though VirtualBox still is not ready for the next Windows version; it has no TPM capability at the moment. Nevertheless, I was able to get something after a fresh installation that removed whatever files were on the disk image. That meant that I needed to mount the old version to get at those files again.
While renaming partially helped with this, what I really needed to do was change the UUID, so VirtualBox would not report a collision between two disk images with the same UUID. To avoid this, the UUID of one of the disk images had to be changed and a command like the following was used to accomplish this:
VBoxManage internalcommands sethduuid [Virtual Disk Image Name].vdi
Because I was doing this on Linux Mint, I could call VBoxManage without need to tell the system where it was, as would be the case on Windows. Otherwise, it is the sethduuid portion that changes the UUID as required. Another way around this is to clone the VDI file using the following command, but I had not realised that at the time:
VBoxManage clonevdi [old virtual disk image].vdi [new virtual disk image].vdi
It appears that there can be more than one way to do things in VirtualBox at times, so the second way will remain on reference for the future.
Sorting out sluggish start-up and shutdown times in Linux Mint 19
9th August 2018The Linux Mint team never forces users to upgrade to the latest version of their distribution, but curiosity often provides a strong enough impulse for me to do so. When I encounter rough edges, the wisdom of leaving things unchanged becomes apparent. Nevertheless, the process brings learning opportunities, which I am sharing in this post. It also allows me to collect various useful titbits that might help others.
Again, I went with the in-situ upgrade option, though the addition of the Timeshift backup tool means that it is less frowned upon than once would have been the case. It worked well too, apart from slow start-up and shutdown times, so I set about tracking down the causes on the two machines that I have running Linux Mint. As it happens, the cause was different on each machine.
On one PC, it was networking that holding up things. The cause was my specifying a fixed IP address in /etc/network/interfaces instead of using the Network Settings GUI tool. Resetting the configuration file back to its defaults and using the Cinnamon settings interface took away the delays. It was inspecting /var/log/boot.log that highlighted problem, so that is worth checking if I ever encounter slow start times again.
As I mentioned earlier, the second PC had a very different problem, though it also involved a configuration file. What had happened was that /etc/initramfs-tools/conf.d/resume contained the wrong UUID for my system's swap drive, so I was seeing messages like the following:
W: initramfs-tools configuration sets RESUME=UUID=<specified UUID for swap partition>
W: but no matching swap device is available.
I: The initramfs will attempt to resume from <specified file system location>
I: (UUID=<specified UUID for swap partition>)
I: Set the RESUME variable to override this.
Correcting the file and executing the following command resolved the issue by updating the affected initramfs image for all installed kernels and speeded up PC start-up times:
sudo update-initramfs -u -k all
Though it was not a cause of system sluggishness, I also sorted another message that I kept seeing during kernel updates and removals on both machines. This has been there for a while and causes warning messages about my system locale not being recognised. The problem has been described elsewhere as follows: /usr/share/initramfs-tools/hooks/root_locale is expecting to see individual locale directories in /usr/lib/locale, but locale-gen is configured to generate an archive file by default. Issuing the following command sorted that:
sudo locale-gen --purge --no-archive
Following these, my new Linux Mint 19 installations have stabilised with more speedy start-up and shutdown times. That allows me to look at what is on Flathub to see what applications and if they get updated to the latest version on an ongoing basis. That may be a topic for another entry on here, but the applications that I have tried work well so far.