Protecting object data from loss

The StorageGRID system provides you with two mechanisms to protect object data from loss: replication and erasure coding.

Replication

When StorageGRID matches objects to an ILM rule that is configured to create replicated copies, the system creates exact copies of object data and stores them on different Storage Nodes or Archive Nodes. ILM rules dictate the number of copies made, where those copies are stored, and for how long they are retained by the system. If a copy is lost as a result of a Storage Node loss, the object is still available if a copy of it exists elsewhere in the StorageGRID system.

Erasure coding

When StorageGRID matches objects to an ILM rule that is configured to create erasure-coded copies, it slices object data into data fragments, computes additional parity fragments, and stores each fragment on a different Storage Node. When an object is accessed, it is reassembled using the stored fragments. If a data or a parity fragment becomes corrupt or lost, the erasure coding algorithm can recreate that fragment using a subset of the remaining data and parity fragments. ILM rules and erasure coding profiles determine the erasure coding scheme used.