In this paper, we qualitatively and quantitatively discuss the design choices, production experience, and lessons in building the Elastic Block Storage ( EBS ) at Alibaba Cloud over the past decade. To cope with hardware advancement and users’ demands, we shift our focus from design simplicity in EBS1 to high performance and space efficiency in EBS2 , and finally reducing network traffic amplification in EBS3 . In addition to the architectural evolutions, we also summarize development lessons and experiences as four topics, including: (i) achieving high elasticity in latency, throughput, IOPS, and capacity; (ii) improving availability by minimizing the blast radius of individual, regional, and global failure events; (iii) identifying the motivations and key tradeoffs in various hardware offloading solutions; and (iv) identifying the pros/cons of alternative solutions and explaining why seemingly promising ideas would not work in practice.

Pliable index coding studies flexible communication networks where each receiver just needs to receive any message that it does not already have. In this work, we consider a more practical but restricted scenario where each receiver wants any message it does not have from a particular subset of messages. We first adapt coding schemes from pliable index coding to this new restricted pliable index coding setting. We show that the adapted scheme is optimal under certain conditions. We simplify the computational complexity when constructing coding schemes for restricted pliable index coding from exponential to linear. We also construct two new coding schemes for the restricted setting, which can outperform the adapted scheme.