A Logical Volume is the block device that the filesystem sees. It is allocated from the Volume Group’s pool of Physical Extents, and it is the layer where the administrator’s capacity decisions become a mountable device. The LV is not a partition; it has no fixed position on a disk, and its extents can be…
A Volume Group is the pool in the middle of the LVM stack. It sits between the Physical Volumes that provide raw capacity and the Logical Volumes that consume it. The VG aggregates the capacity of its member PVs into a single address space, and the administrator allocates LVs from that address space without knowing…
A Physical Volume (PV) is the foundation of the LVM stack. It is a block device—a whole disk, a partition, or a software RAID device—that has been initialized with LVM metadata. The initialization writes a label and a metadata area to the device, which records its identity and its membership in a Volume Group. Until…
Logical Volume Management inserts a layer between the physical disk and the filesystem. The disk is no longer the unit of allocation; the filesystem is created on a logical volume that can span multiple disks, be resized while mounted, and be moved between physical devices without unmounting. The LFCS storage domain treats LVM as the…
A UUID is a 128-bit identifier stored in a filesystem’s metadata, assigned when the filesystem is created. It identifies the filesystem itself, not the device slot it occupies. The /etc/fstab man page states the recommendation directly: UUID= or LABEL= should be used instead of a device name, because device names are “often a coincidence of…
Clippy is not a separate linter that happens to understand Rust. It is a collection of lint passes that run inside the compiler, using the same HIR and type information that the rest of rustc uses. Adding a custom lint means writing a pass that implements EarlyLintPass or LateLintPass, registering it with the compiler’s lint…
Rust offers two mechanisms for polymorphism, and the choice between them determines what the compiler generates. Monomorphization produces a separate copy of the function for every concrete type it is called with, enabling inlining and constant propagation at the cost of code size. Dynamic dispatch produces a single copy that consults a vtable at runtime,…
The borrow checker does not run on the HIR. It runs on the MIR, a representation that is small enough, explicit enough, and control-flow-based enough to make the borrow checker’s analysis tractable. The MIR is the compiler’s last representation before code generation, and the borrow checker’s phases—dataflow, region inference, and the final error walk—operate on…
The Rust compiler does not type-check the syntax tree you write. Between the parser and the type checker sits a lowering step that converts the Abstract Syntax Tree (AST) into the High-Level Intermediate Representation (HIR). This step is not a refactoring for cleanliness. It is where syntactic sugar is dissolved, where for loops become loop…
Performance work in Rust follows a discipline that is easy to state and hard to practice: measure first, optimize the bottleneck, measure again. The tools that make this possible are the profilers that show where time is actually spent, the benchmarking frameworks that turn a measurement into a repeatable experiment, and the SIMD APIs that…