Ceph

What is the workflow of writing data to Ceph?

Difficulty: unrated

Source: bregman-arie/devops-exercises by Arie Bregman

Answer

The work flow is as follows:

  1. The client sends a request to the ceph cluster to retrieve data
  2. The client retrieves the latest cluster map from the Ceph Monitor
  3. The client uses the CRUSH algorithm to map the object to a placement group. The placement group is then assigned to a Ceph OSD Daemon dynamically.
  4. The client sends the data to the primary OSD of the determined placement group. If the data is stored in an erasure-coded pool, the primary OSD is responsible for encoding the object into data chunks and coding chunks, and distributing them to the other OSDs.