Ceph: Designing and Implementing Scalable Storage Systems

How it works...

Now that we know how to edit the Ceph CRUSH map, let's understand what's inside the CRUSH map. A CRUSH map file contains four main sections; they are as follows:

• Devices: This section of the CRUSH map keeps a list of all the OSD devices in your cluster. The OSD is a physical disk corresponding to the ceph-osd daemon. To map the PG to the OSD device, CRUSH requires a list of OSD devices. This list of devices appears in the beginning of the CRUSH map to declare the device in the CRUSH map. The following is the sample device list:

• Bucket types: This defines the types of buckets used in your CRUSH hierarchy. Buckets consist ...