Diskless

Diskless refers to computer systems that operate without a local hard disk or other persistent storage. In a diskless configuration, the operating system and most applications are loaded over a network from centralized servers at boot time, and runtime data may be kept in memory or on remote storage. Diskless clients are common in environments such as computer labs, classrooms, high-performance computing clusters, and thin-client deployments, where centralized management and easy re provisioning are advantageous.

Booting and operation typically rely on network services. A client uses a network boot protocol like PXE to obtain an IP address and locate a boot server via DHCP. A bootloader such as pxelinux or iPXE is fetched over TFTP, then loads a kernel and an initial RAM filesystem. The kernel mounts its root filesystem from a remote location, usually via NFS or iSCSI, and runs as a normal system. Root filesystems are frequently read-only, with writable areas provided in RAM or on network shares. Ongoing I/O depends on the network and the remote storage services.

Technologies and configurations commonly involved include PXE or iPXE, DHCP, TFTP for boot files, and NFS or iSCSI for the root filesystem. Diskless setups are often managed with centralized image servers and tools that deploy OS images and updates to many clients. Some implementations use RAM disks for temporary storage or caching to improve performance.

Advantages of diskless systems include reduced hardware costs, simpler mass provisioning, and centralized management of images and security patches. Drawbacks include reliance on network availability and server capacity, potential boot delays, and the complexity of setup and troubleshooting. Diskless configurations are well suited for labs, classrooms, kiosks, and other environments requiring rapid, uniform provisioning.