SSD cache expansion using overprovisioned space

摘要

The invention provides for SSD cache expansion by assigning all excess overprovisioned space (OP) above a level of advertised SSD memory to SSD cache. As additional SSD memory is needed to provide the advertised SSD memory, an offsetting portion of the OP is reassigned from excess overprovisioned space to the SSD cache. In this manner, the advertised SSD memory is maintained while continuously allocating all available excess OP to cache. The result is that all of the available SSD memory is allocated to cache, a portion to maintain the advertised SSD memory and the balance as excess OP allocated to cache. This eliminates idle OP in the SSD allocation.

主权项

1. A solid state drive (SSD) cache capacity expander, comprising:
a SSD memory having an initial physical memory capacity and excess overprovisioned memory comprising physical memory capacity above an advertised SSD cache memory capacity; a SSD controller configured to allocate the excess overprovisioned memory to SSD cache such that the SSD cache capacity is initially equal to the SSD physical memory capacity, the SSD controller further configured to detect a reduction in the physical memory capacity of the SSD during ordinary computer operations, the SSD controller further configured to reallocate a portion of the excess overprovisioned memory allocated to SSD to advertised SSD capacity to maintain the advertised capacity of the SSD while reducing the allocation of excess overprovisioned space (OP) to SSD cache such that the adjusted SSD cache capacity is equal to the adjusted SSD physical memory capacity.