Adaptive over-provisioning in memory systems

A method for data storage, comprising:

• in a memory that includes multiple memory blocks, predefining a range of logical addresses for storing data in the memory;
• defining a number of physical storage locations in the memory blocks, such that data storage in the number of the physical storage locations retains in the memory blocks memory areas that do not hold valid data and whose aggregated size is at least commensurate in size with an initial over-provisioning overhead;
• at a first time, storing the data in the memory by mapping the logical addresses to the number of physical storage locations, while complying with the initial over-provisioning overhead, and compacting portions of the data from one or more previously-programmed memory blocks containing one or more of the retained memory areas;
• and
• at a second time subsequent to the first time, defining a modified over-provisioning overhead that is different from the initial over-provisioning overhead, modifying the number of the physical storage locations so as to comply with the modified over-provisioning overhead, and continuing to store the data by mapping the logical addresses to the modified number of the physical storage locations and compacting the data portions;
• wherein defining and modifying the number of physical storage locations comprise applying a mapping process, which maps between the logical addresses and the physical storage locations and which varies in accordance with the over-provisioning overhead.

Apparatus for data storage, comprising:

• a memory, comprising multiple memory blocks;
• and
• a processor, which is configured to specify at a first time a first over-provisioning overhead and store data in the memory while retaining in the memory blocks memory areas, which do not hold valid data and whose aggregated size is at least commensurate in size with the specified first over-provisioning overhead, to compact portions of the data from one or more previously-programmed memory blocks containing one or more of the retained memory areas, and, at a second time subsequent to the first time, to specify a second over-provisioning overhead that is different from the first over-provisioning overhead and to continue to store the data and compact the data portions while complying with the second over-provisioning overhead;
• wherein the processor is configured to encode the data at the first time with an Error Correction Code (ECC) having a given redundancy level and store the encoded data, and to specify the second over-provisioning overhead by modifying the given redundancy level of the ECC.

Apparatus for data storage, comprising:

• a memory, comprising multiple memory blocks;
• and
• a processor, which is configured to predefine a range of logical addresses for storing data in the memory, to define a number of physical storage locations in the memory blocks, such that data storage in the number of the physical storage locations retains in the memory blocks memory areas that do not hold valid data and whose aggregated size is at least commensurate in size with an initial over-provisioning overhead, to store data in the memory at a first time by mapping the logical addresses to the number of the physical storage locations, while complying with the initial overprovisioning overhead, and compacting portions of the data from one or more previously-programmed memory blocks containing one or more of the retained memory areas, and, at a second time subsequent to the first time, to define a modified over-provisioning overhead that is different from the initial over-provisioning overhead, to modify the number of the physical storage locations so as to comply with the modified over-provisioning overhead, and to continue to store the data by mapping the logical addresses to the modified number of the physical storage locations and compact the data portions;
• wherein the processor is configured to apply a mapping process, which maps between the logical addresses and the physical storage locations and which varies in accordance with the over-provisioning overhead.