Linux - The Next GenerationWhile investigating ZFS snapshot problems I was looking into Ubuntu 24.04 initial RAM disks (initrd/initramfs). So here’s what I found. Unpacking RAM disk Over the years many different ways to pack a RAM disk were used (things like cpio archives, squashfs, and so on). Since it has been a long time since I was forced […]
While experimenting with encrypted ZFS root file systems, I encountered some odd behavior concerning snapshots: I had created a separate /etc file system with snapshots. The listing of the snapshots shows up, however all snapshot directories were empty: However zfs reported, that the snapshots contain data, so I guess the snapshots are created, they’re just […]
In order to investigate a possible Ubuntu server installation on top of (encrypted) ZFS, I decided to first do this with the desktop version. Reason for that is simple: The desktop version of the installer contains an option to install on a root ZFS volume (guess what: the server version does not). So I started […]
ZFS comes with quite a set of features. However when upgrading zfs, new features are not enabled by default for compatibility reasons. This may be reported by zpool status: In order to get more information about possible new features you can use zpool upgrade: You can add option -v to get more detailed information about […]
One nice feature of filesystems like btrfs of zfs is snapshots. They preserve a certain state of a filesystem without wasting too much space (as long as the modification rate is low). In some cases it is fine to create a snapshot manually from time to time, however on several occasions I wished I had […]
Last week I had a little chat with a very good friend of mine. We were talking about how to best configure his new home server. One of the topics was the choice of filesystems which resulted in a longer discussion with some other friends (all long term IT people and Linux enthusiasts). So I […]
What’s block cloning? Block cloning allows to copy files (or parts of it = blocks) without allocating extra space (besides the metadata required for filename, attributes, or the references to existing on disk blocks). Similar techniques are used to implement things like snapshots or deduplication in filesystems supporting them. In practice this feature is very […]