Controlled Replication Under Scalable Hashing

What is CRUSH?

CRUSH stands for “Controlled Replication Under Scalable Hashing” and It is the algorithm in charge of placing data at every disk’s device of the cluster

CRUSH distributes data evenly across available object storage devices in what is often described as a pseudo-random manner. CRUSH’s settings are defined through a compiled map called a CRUSH map. The map, which can be customized by the storage administrator, informs the cluster about the layout and capacity of nodes in the storage network and specifies how redundancy should be managed.

CRUSH replicates data in multiple locations and fault domains. So when a disk fails, CRUSH replicates data across available OSDs. There is no need for RAID, which typically just adds to the hardware cost. – See more at: http://www.inktank.com/ceph/ceph-the-crush-difference/#sthash.jXB6B0Qw.dpuf

Controlled Replication Under Scalable Hashing