Disks, SSDs & NVMe
HDDs, SSDs, NVMe, and how the kernel sees them Before looking at devices, it helps to see where they sit. A userspace write travels through multiple…
Linux Storage
Partitions (MBR & GPT)
MBR, GPT, and how disk space gets divided A block device is a flat array of LBAs — 0, 1, 2, …, N-1. A partition is nothing more than a named range of those…
Filesystem Fundamentals
Inodes, journaling, VFS, and how files are actually stored A filesystem is a data structure laid out on top of a block device. The block device exposes a…
ext4 & XFS
The two mainstream Linux filesystems — internals and trade-offs On a modern Linux system, the default root filesystem is almost always ext4 (Debian, Ubuntu)…
RAID Levels
Combining disks for performance, redundancy, or both RAID — Redundant Array of Independent Disks (originally "Inexpensive" in the 1988 Berkeley paper by…
Linux Software RAID (mdadm)
Managing arrays with the Linux MD subsystem mdadm (multi-disk admin) is the userspace administration tool for the Linux kernel's MD (Multiple Device)…
Device Mapper
The kernel framework behind LVM, LUKS, and thin pools Consider a typical laptop: ext4 on top of an LVM logical volume, LVM on top of a LUKS-encrypted…
LVM Fundamentals
Physical Volumes, Volume Groups, and Logical Volumes LVM (Logical Volume Manager) is an abstraction layer that sits between raw block devices and the…
Thin Provisioning & Snapshots
Allocate on demand, snapshot at scale Thin provisioning decouples the size an LV advertises from the capacity it has actually consumed. Multiple thin LVs…
dm-crypt & LUKS
Full-disk encryption the Linux way Linux full-disk encryption is built from two independent layers that are almost always used together, but it's critical to…
LUKS Keys, crypttab & Auto-Unlock
Multiple unlock methods and integrating with systemd LUKS's defining feature for operators is that a single master key can be unlocked by multiple…
TPM Fundamentals
Trusted Platform Module — sealing secrets to hardware state A Trusted Platform Module is a dedicated secure crypto-processor specified by the Trusted…
Secure Boot & LUKS Auto-Unlock
Tying UEFI, TPM, and LUKS together Secure Boot is a UEFI feature that enforces signature checks on every boot-time EFI binary. Before executing anything, the…
ZFS
The integrated filesystem, volume manager, RAID, and integrity layer ZFS was developed at Sun Microsystems starting in 2001 and marketed as “the last word in…
btrfs
Linux-native copy-on-write filesystem btrfs (B-Tree FS, pronounced butter FS or better FS) started at Oracle in 2007 and has been in the mainline Linux…
