Part III Storing Data in a Cluster #
- 17 Stored data management
The CRUSH algorithm determines how to store and retrieve data by computing data storage locations. CRUSH empowers Ceph clients to communicate with OSDs directly rather than through a centralized server or broker. With an algorithmically determined method of storing and retrieving data, Ceph avoids a…
- 18 Manage storage pools
Ceph stores data within pools. Pools are logical groups for storing objects. When you first deploy a cluster without creating a pool, Ceph uses the default pools for storing data. The following important highlights relate to Ceph pools:
- 19 Erasure coded pools
Ceph provides an alternative to the normal replication of data in pools, called erasure or erasure coded pool. Erasure pools do not provide all functionality of replicated pools (for example, they cannot store metadata for RBD pools), but require less raw storage. A default erasure pool capable of s…
- 20 RADOS Block Device
A block is a sequence of bytes, for example a 4 MB block of data. Block-based storage interfaces are the most common way to store data with rotating media, such as hard disks, CDs, floppy disks. The ubiquity of block device interfaces makes a virtual block device an ideal candidate to interact with …