Health Data Availability Protection: Delta-XOR-Relay Data Update in Erasure-Coded Cloud Storage Systems

Abstract

To achieve the high availability of health data in erasure-coded cloud storage systems, the data update performance in erasure coding should be continuously optimized. However, the data update performance is often bottlenecked by the constrained cross-rack bandwidth. Various techniques have been proposed in the literature to improve network bandwidth efficiency, including delta transmission, relay, and batch update. These techniques were largely proposed individually previously, and in this work, we seek to use them jointly. To mitigate the cross-rack update traffic, we propose DXR-DU which builds on four valuable techniques: (i) delta transmission, (ii) XOR-based data update, (iii) relay, and (iv) batch update. Meanwhile, we offer two selective update approaches: 1) data-delta-based update, and 2) parity-delta-based update. The proposed DXR-DU is evaluated via trace-driven local testbed experiments. Comprehensive experiments show that DXR-DU can significantly improve data update throughput while mitigating the cross-rack update traffic.