Ceph Level 1 – Foundations

Ceph is an open-source distributed storage platform created to deliver scalable, software-defined block, object and file storage on commodity hardware. Originally developed by Sage Weil and now stewarded through the wider upstream Ceph community with strong enterprise backing, it was designed around goals such as resilience, horizontal scale, self-healing behaviour and removal of traditional storage bottlenecks through intelligent data distribution.


This module introduces Ceph as a distributed storage platform and explains the architectural concepts learners need before they can operate or troubleshoot it properly, giving them the right foundation for understanding how data moves through the cluster and why Ceph is widely used in scale-out infrastructure and Proxmox-backed storage environments.

Course purpose

Give learners a solid grounding in how Ceph works as distributed storage, so they can understand the platform architecture, follow the path of data through the cluster, and build the right mental model before moving into operations or troubleshooting.

Suggested duration

  • 1 day
  • or 1.5 days with labs

Target audience

  • storage administrators
  • platform engineers
  • Proxmox administrators using Ceph-backed storage
  • engineers new to distributed storage

Prerequisites

  • Linux command-line basics
  • basic storage concepts
  • general networking knowledge

Learning outcomes

  • explain what Ceph is and where it fits
  • describe how Ceph stores and distributes data
  • understand the relationship between RADOS, pools, PGs and CRUSH
  • identify the main Ceph daemon roles
  • explain the basic flow of data through the cluster

Detailed module structure

Unit 1: What Ceph is and where it fits

Topics:

  • Ceph as distributed, software-defined storage
  • block, object and file interfaces
  • common deployment scenarios
  • why Ceph is attractive for scale-out infrastructure
  • trade-offs: complexity, consistency, recovery overhead, operational discipline

Unit 2: Core architecture and data flow

Topics:

  • how clients interact with the cluster
  • object-based internal design
  • introduction to RADOS
  • how data is broken up, placed and replicated
  • why Ceph avoids traditional central metadata bottlenecks for object placement

Unit 3: RADOS and object storage concepts

Topics:

  • what RADOS provides
  • objects and object collections
  • logical vs physical data placement
  • how higher-level services build on top of RADOS

Unit 4: Pools and placement groups

Topics:

  • what pools are for
  • logical separation of data
  • how placement groups act as distribution units
  • why PG sizing matters
  • operational impact of too few or too many PGs

Lab ideas:

  • inspect cluster pool configuration
  • view PG distribution at a high level

Unit 5: CRUSH and data placement

Topics:

  • what CRUSH is
  • deterministic data placement
  • failure domains
  • topology-aware placement
  • why CRUSH removes the need for lookup tables in the traditional sense

Lab ideas:

  • inspect a CRUSH hierarchy
  • discuss how host/rack failure domains affect resilience

Unit 6: Ceph daemons and their roles

Topics:

  • MON
  • MGR
  • OSD
  • MDS
  • optionally RGW if relevant to your environment
Standard naming: MON = monitor, MGR = manager, OSD = object storage daemon, MDS = metadata server.

Lab ideas:

  • identify daemon roles in a live or lab cluster
  • map services to their operational responsibilities

Assessment

Short concept check

  • explain pool vs PG
  • explain CRUSH at a high level
  • identify daemon roles

Architecture walkthrough

“What happens when a client writes data to Ceph?”

Distributed storage fundamentals - Clear architectural understanding - Better operational confidence

Ideal for engineers building their first proper mental model of Ceph