Multi-Mode Low-Latency Software-Defined Error Correction for Data Centers
Fakhreddine Ghaffari, Ali Akoglu, Bane V. Vasic, David Declercq · 2017
Flash memories are gaining prominence for utilizing in large scale data centers (DCs) due to their high memory density, low power consumption and heat dissipation, and high access speed characteristics. The rate of degradation for a flash memory is largely affected by the amount and frequency of the erase/write operations, which is a challenge in the DC context that serves dynamically changing workloads. Adaptive Error Correction Code (AECC) schemes have been introduced for changing the error correction algorithm based on the reliability state of the flash. In this study we show that hard decision (bit-flipping) and soft decision decoding (Belief Propagation) class of algorithms for Low Density Parity Check (LDPC) decoders complement each other for utilizing in the flash based DCs in order to meet the dynamically changing reliability level. We propose a new family of ECC to improve the reliability of flash memory. Our Monte-Carlo simulations and Field Programmable Gate Array (FPGA) based hardware implementation analysis show that LDPC decoders are suitable for balancing the throughput, decoding performance and reliability requirements in DCs.