Setting up an NTP server chrony is the default service on newer OS releases (Red Hat 7.2 and later, any recent Ubuntu release). chrony has several advantages over ntpd: Quicker synchronisation. Better response to changes in clock frequency (very useful for VMs). Periodic polling of time servers isn’t required. It lacks some features like broadcast,… Read More: NTP: Setting up an NTP server »
In a previous life, I designed and built many SANs based on Xsan (I believe I started with Xsan 1.3). I then migrated to looking after SANs based on SNFS, either from 3rd party vendors, or Quantum. I believe that the age of Fibre Channel is long over (although SNFS also works on Infiniband if… Read More: SNFS/Xsan: Quantum SNFS metadata controller and Xsan client compatibility chart »
The easiest way is using an application like Onyx. You can check the amount of space taken by the files using du. Before using any deletion command you can check with ls what exactly is going to be deleted. When using rm enable verbose mode (-v). Don’t delete the root folders, just the files contained… Read More: macOS : Removing caches and temporary files in macOS »
I have been trying to document the process of configuring a Raspberry Pi as a Time Machine Capsule, but the article became far too long. It covered far too much information and was really hard to read. I then decided to break the stages into more manageable steps. This has the advantage of allowing the… Read More: Raspberry Pi: Installing, hardening and optimising Ubuntu 20.04 Server »
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 has been very stable and… Read More: Ubuntu: Installing/fixing TP-Link AC1200 (T4UH 1.0) drivers in Ubuntu 20.04… »
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 to have been modified from… Read More: macOS: Application stealing focus »
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 will discard unused blocks on… Read More: VirtualBox/KVM: Reduce VM sizes »
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, and there is something in… Read More: Ubuntu 20.4: Virtualbox not running after the last upgrade »
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 are run together and have… Read More: Ubuntu: ZFS bpool is full and not running snapshots during… »
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 that one of the CPU… Read More: Ubuntu: System freezing for a few seconds with iwlwifi microcode… »