Abstract: Data being stored in a block of flash memory system may be characterized as being frequently modified or infrequently modified (hot/cold) based on a heuristic. When performing garbage collection, if the data from hot blocks is consolidated and data from cold blocks is separately consolidated by writing the data to different free blocks, the number of write operations to perform the garbage collection may be reduced. The lower “write amplification” contributes to increasing the lifetime of the memory circuit. When the number of blocks in a pool of previously erased blocks is reduced to a threshold value, a block having data previously stored therein may be selected for garbage collection based on a second heuristic.

Abstract: Data de-duplication uses a hash of a scrambled data block as an address where the data block is stored to. The data storage system has multiple replication nodes, each storing only one copy of the data. Each replication node is assigned a unique identifier that is a seed to initialize a data scrambler. Each replication node scrambles the data to a different scrambled data value, since each node has a different unique identifier. Each node's scrambled data is cryptographically hashed to generate a different hash for each replication node. The hash is the address that the scrambled data is stored to in that replication node. Each replication node stores a different scramble of the data, and stores it to a different physical location due to the different hash. Thus the data is stored to diverse physical locations on different replication nodes, reducing systematic errors. All hashes are stored as metadata.

Abstract: Data being stored in a block of flash memory system may be characterized as being frequently modified or infrequently modified (hot/cold) based on a heuristic. When performing garbage collection, if the data from hot blocks is consolidated and data from cold blocks is separately consolidated by writing the data to different free blocks, the number of write operations to perform the garbage collection may be reduced. The lower “write amplification” contributes to increasing the lifetime of the memory circuit. When the number of blocks in a pool of previously erased blocks is reduced to a threshold value, a block having data previously stored therein may be selected for garbage collection based on a second heuristic.

Abstract: The storage system uses a combination of checkpoint data and journal data to reconstruct an indirection table. The checkpoint data comprises compacted media addresses from the indirection table that are then stored in a relatively few number of media blocks. This allows the media controller to quickly read the compacted checkpoint data from the solid state media. The media controller generates the journal data from logical addresses and associated media addresses for additional write operations received while creating the checkpoint data. The media controller uses metadata when errors are identified in the checkpoint data or journal data.

Abstract: A memory system contains solid state media for storing data and uses volatile memory for storing an indirection table. The indirection table maps client addresses to media addresses in the solid state media. The solid state media also stores metadata summaries maintaining the mappings of the client addresses to the media addresses within the solid state media. A media controller is configured to reconstruct the indirection table in the volatile memory from the metadata summaries stored in the solid state media based on block timestamps identifying when the metadata summaries were stored in the solid state media.

Abstract: Data being stored in a block of flash memory system may be characterized as being frequently modified or infrequently modified (hot/cold) based on a heuristic. When performing garbage collection, if the data from hot blocks is consolidated and data from cold blocks is separately consolidated by writing the data to different free blocks, the number of write operations to perform the garbage collection may be reduced. The lower “write amplification” contributes to increasing the lifetime of the memory circuit. When the number of blocks in a pool of previously erased blocks is reduced to a threshold value, a block having data previously stored therein may be selected for garbage collection based on a second heuristic.