Episode 155 of The Linux Podcast dives into Bcache, the Linux kernel block-layer caching that lets you put a fast SSD in front of slow spinning disks. Lucas and Luna walk through how Bcache works at the block level, why it's different from filesystem-level caching, and where it shines—like speeding up database storage or home lab NAS builds without ripping out existing drives. They break down the key concepts: caching modes (writeback, writethrough, writearound), the bucket and priority cache structure, and how to attach a cache device to a backing device. They also touch on real-world performance numbers, like how Bcache can slash read latency from tens of milliseconds to under a millisecond for hot data, and discuss the trade-offs, including writeback risks and the importance of a UPS. The episode wraps with a look at Bcachefs, the next-gen filesystem that builds on Bcache's ideas, and a practical tip for anyone considering Bcache in their own setup. If you've ever wanted to squeeze more life out of old hard drives, this is the episode for you.

#Bcache #Linux #BlockCaching #SSD #HDD #Storage #Kernel #Filesystem #Bcachefs #NAS #HomeLab #Performance #Writeback #Writethrough #Technology #OpenSource #FexingoBusiness #BusinessPodcast

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In this episode of The Linux Podcast with Fexingo, Lucas and Luna dig into the inner workings of Linux Control Groups, or cgroups, and how they keep modern containerized systems stable. Using a real-world example of a platform running ten thousand containers on a single host, they explain how cgroups manage CPU, memory, and I/O resources to prevent one runaway process from taking down the whole system. They walk through the difference between cgroups version one and version two, and why version two's unified hierarchy is a game changer for managing resources across large fleets. Lucas also highlights the delicate interplay between cgroups and the OOM killer, and how systemd integrates cgroups to make container orchestration safer. The conversation stays practical, touching on how engineers can monitor cgroup metrics with tools like systemd-cgls and the ps command, and what happens when limits are set too tight or too loose. If you've ever wondered how a single kernel feature keeps massive container deployments from collapsing, this episode gives you a clear, grounded explanation. Tune in for a deep but accessible look at a foundational Linux technology.

#Linux #ControlGroups #Cgroups #Containers #Systemd #Kernel #ResourceManagement #ServerAdministration #DevOps #Virtualization #OOMKiller #ProcessIsolation #Technology #OpenSource #FexingoBusiness #BusinessPodcast #TechPodcast #SysAdmin

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In this episode, Lucas and Luna dive into cgroups v2, the kernel feature that underpins container resource management. They explain how cgroups limit CPU, memory, and I/O for individual processes, and how systemd integrates with cgroups to manage services. The conversation covers the shift from cgroups v1 to v2, the role of cgroups in container runtimes like Docker and Kubernetes, and a practical example of setting memory limits. They also touch on why cgroups matter for security and multi-tenant environments. If you've ever wondered how your containers stay within their resource bounds, this episode breaks it down with clarity and real-world context.

#Linux #Cgroups #Containers #Docker #Kubernetes #Systemd #Kernel #ResourceManagement #CPU #Memory #IO #Virtualization #DevOps #CloudNative #Technology #FexingoBusiness #BusinessPodcast #OpenSource

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In this episode, Lucas and Luna explore User Mode Linux (UML), a technology that lets you run Linux as a regular user-space process on an existing Linux host. They explain how UML differs from containers and virtual machines, dive into its performance trade-offs, and share practical use cases like kernel development, security testing, and teaching. They also discuss the recent revival of UML in the context of modern kernel development and why it remains relevant in 2026. If you've ever wanted to experiment with kernels or build a lightweight test environment without buying extra hardware, this episode gives you the concrete details you need to get started.

#UserModeLinux #LinuxKernel #Virtualization #HomeLab #KernelDevelopment #LinuxSecurity #OpenSource #LinuxTips #SystemsAdmin #DevOps #Linux #Technology #FexingoBusiness #BusinessPodcast #TechPodcast #LinuxPodcast #KernelDebugging #LinuxDistros

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In this episode of The Linux Podcast, Lucas and Luna explore how FUSE (Filesystem in Userspace) lets ordinary programs implement file systems without touching kernel code. They trace the journey of an SSHFS mount, showing how a read request travels from the virtual file system layer through the kernel's FUSE module and into a user-space daemon, then back again. They discuss the performance overhead of passing data through /dev/fuse, the role of the kernel's page cache in mitigating that cost, and how FUSE powers everything from cloud storage clients to container volume plugins. Lucas brings up the example of GlusterFS and contrasts FUSE's flexibility with the raw performance of kernel-native file systems like EXT4 and XFS. Luna challenges him on when you'd actually choose FUSE for production, and they land on its sweet spot: low-to-moderate workloads where rapid iteration and ease of development matter more than squeezing out every last operation per second. They close by mentioning how FUSE has even influenced new kernel APIs, and they point listeners to the Fexingo podcast network for more deep dives into Linux and open source software.

#Linux #FUSE #FilesystemInUserspace #SSHFS #GlusterFS #OpenSource #Technology #Kernel #UserSpace #VirtualFileSystem #ContainerStorage #CloudStorage #SystemAdministration #DevOps #FexingoBusiness #BusinessPodcast #TechPodcast #LinuxPodcast

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In this episode of The Linux Podcast, Lucas and Luna dive into Kernel Samepage Merging (KSM), a memory-saving feature that deduplicates identical pages across processes. They explore how KSM works, why it's a game-changer for virtualized environments like QEMU/KVM, and how it can significantly cut memory costs in cloud data centers. Using the example of a large-scale deployment running hundreds of identical VMs, they walk through the mechanics of KSM's scan and merge process, the trade-offs in CPU usage, and best practices for tuning. They also touch on recent improvements in detection algorithms and discuss when KSM is worth enabling versus when it might be more trouble than it's worth. Perfect for system administrators and DevOps engineers looking to optimize memory efficiency.

#KernelSamepageMerging #KSM #LinuxMemory #Virtualization #QEMU #KVM #MemoryDeduplication #CloudComputing #ServerOptimization #LinuxKernel #SystemAdministration #DevOps #MemoryManagement #OpenSource #Technology #FexingoBusiness #BusinessPodcast #LinuxPodcast

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In this episode, Lucas and Luna explore io_uring's role in modern database performance, focusing on how PostgreSQL and MySQL benefit from asynchronous I/O. They break down the syscall overhead problem, the role of SQEs and CQEs, and real-world results from benchmarks on NVMe storage. They also discuss the trade-offs of using io_uring with native AIO, and how it integrates with popular database engines. By the end, you'll understand why io_uring is a game-changer for high-throughput workloads, and what to consider before deploying it in production. Tune in for a deep dive into one of Linux's most impactful I/O innovations.

#Linux #io_uring #DatabasePerformance #PostgreSQL #MySQL #AsynchronousIO #Storage #NVMe #SystemsProgramming #OpenSource #Technology #FexingoBusiness #BusinessPodcast #LinuxKernel #PerformanceEngineering #ServerStack #CloudComputing #DevOps

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In this episode of The Linux Podcast with Fexingo, Lucas and Luna dive into Landlock, the Linux security module that lets unprivileged processes sandbox themselves. They explain how Landlock differs from traditional access control and container isolation, using a practical example of running a browser or a server with restricted filesystem access. They discuss the origins of the project, its current status in the kernel, and how it complements other security features like seccomp and namespaces. The conversation highlights real-world use cases, including sandboxing untrusted applications and protecting against supply chain attacks. If you're a developer or sysadmin looking to harden your systems without root, this episode gives you a concrete tool to add to your arsenal.

#Landlock #LinuxSecurity #LSM #Sandboxing #Unprivileged #AccessControl #Kernel #Sysadmin #SecurityModule #OpenSource #Technology #Linux #FexingoBusiness #BusinessPodcast #Podcast #TechPodcast #DeveloperTools #SystemHardening

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Lucas and Luna dig into systemd's automount units, explaining how Linux can defer mounting network filesystems until they're actually accessed. They walk through a real-world scenario: a large NFS share on a laptop that only mounts when you open the directory, saving boot time and battery. The episode covers the underlying autofs mechanism, the systemd .mount and .automount unit pairing, how systemd's automount differs from traditional autofs, and how it handles network filesystem failures gracefully. Listeners learn the concrete steps to set up an automount unit for an NFS share, plus gotchas like the 'x-systemd.automount' mount option and why you might want to use it for CIFS or SSHFS too. By the end, you'll know when automounting is overkill and when it's a laptop-saver.

#SystemdAutomount #LinuxAutomount #NFS #NetworkFilesystems #Systemd #LinuxAdmin #Autofs #LazyMount #LinuxBootTime #LaptopLinux #SystemdMount #LinuxTips #TechPodcast #OpenSource #LinuxServer #FexingoBusiness #BusinessPodcast #LinuxPodcast

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In this episode of The Linux Podcast with Fexingo, Lucas and Luna dive into user namespaces, the Linux kernel feature that gives containers their security backbone. They explain how user namespaces let unprivileged users run containers safely by mapping container root to a regular user on the host, and why this feature is central to modern container security. The conversation covers the mechanics of uid and gid mapping, the security implications of nested user namespaces, and recent kernel hardening efforts. They also touch on real-world usage in Docker, Kubernetes, and systemd, and discuss a 2024 vulnerability that highlighted the limits of isolation. If you're curious about how containers stay isolated from the host, this episode breaks down a core Linux security mechanism in a clear, practical way.

#UserNamespaces #LinuxKernel #Containers #Security #Docker #Kubernetes #Systemd #PrivilegeEscalation #UnprivilegedContainers #UidMapping #GidMapping #RootlessContainers #OpenSource #Technology #FexingoBusiness #BusinessPodcast #LinuxServer #KernelSecurity

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