Interactive lab
Seven small simulators that run the book's algorithms in your browser: no network, no installation. The arithmetic is a line-by-line port of Ceph's own code and is checked against it by the tests in tests/sims (make check-sims).
CRUSH playgroundBuild a root, hosts and OSDs, choose a rule, and watch straw2 place every PG; mark an OSD out or down or change a weight and see which PGs move.In the book: Chapter 8, Chapter 28PG count calculatorGive the OSD count and each pool's share of the data: see the classic pgcalc answer and what the pg_autoscaler would choose, pass by pass.In the book: Chapter 7Replication or erasure codingChoose k, m and the plugin and compare usable capacity, overhead, the failures each layout survives and the cost of repairing one chunk.In the book: Chapter 13Peering and recovery stepperStep through three stories of one PG with three replicas and watch the PeeringState machine, the up and acting sets and the PG logs.In the book: Chapter 35BlueStore write pathChoose the device, offset and length of a write and watch BlueStore split it and decide what goes through the WAL (deferred) and what is written directly.In the book: Chapter 12RGW PUT and multipartGive a key and a size and follow an S3 PUT through radosgw to the bucket index and the data pool, with the RADOS objects it creates.In the book: Chapter 4RBD striping mapperSet an image's object size, stripe_unit and stripe_count and an I/O's offset and length: see which rbd_data objects it touches and where.In the book: Chapter 37