General considerations for namespace service plans

Initially, when you add an object to a namespace, HCP creates and stores the data on the ingest tier and metadata for the object on primary running storage. For each object that’s stored in a namespace:

1.HCP creates primary metadata for it. This metadata consists of information HCP already knows, such as the creation date, and, for objects only, the data size, hash algorithm, and cryptographic hash value generated by that algorithm. It also includes metadata that was either inherited or specified in the write request, such as retention setting, UID, and GID.

2.HCP creates the number of additional copies of the primary metadata required to satisfy the ingest tier metadata protection level (MPL) that’s set for the namespace by its service plan. HCP then distributes all copies of the primary metadata among the HCP storage nodes.

3.HCP creates the number of copies of the object data required to satisfy the ingest tier data protection level (DPL) that’s set for the namespace by its service plan. HCP then distributes all copies of the object data either among the HCP storage nodes or HCP S Series Nodes, depending on the ingest tier.

Each copy of the primary metadata for the object points to all copies of the object data. However, the object data is not necessarily stored on the same node as the primary metadata for the object.

4.HCP stores a copy of the metadata with each copy of the object data. Each copy, called the secondary metadata, lets HCP reconstruct the primary metadata should that become necessary.

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