Zhe Zhang

Zhe Zhang

Sunnyvale, California, United States
7K followers 500+ connections

About

15 years of experience building distributed systems (and having fun) 🛠️ ⚙️ ⌨️ 😀
7.5…

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Experience

Education

Publications

Patents

Projects

  • HDFS Erasure Coding

    Currently HDFS triplicates each block by default for a number of purposes: 1) protection against DataNode failures; 2) better locality for MapReduce tasks; 3) avoidance of overloaded DataNodes through choosing among multiple replicas. Replication is expensive -- the default triplication scheme has 200% overhead in storage space and other resources (e.g., NameNode memory usage). However, for “cold” and "warm" datasets with low I/O activities, secondary block replicas are rarely accessed during…

    Currently HDFS triplicates each block by default for a number of purposes: 1) protection against DataNode failures; 2) better locality for MapReduce tasks; 3) avoidance of overloaded DataNodes through choosing among multiple replicas. Replication is expensive -- the default triplication scheme has 200% overhead in storage space and other resources (e.g., NameNode memory usage). However, for “cold” and "warm" datasets with low I/O activities, secondary block replicas are rarely accessed during normal operation -- while consuming the same amount of resources as the primary ones. Therefore, a natural improvement is to use Erasure Coding (EC) in place of replication, which provides the same level of fault tolerance with much less storage space. In typical EC setups the storage overhead is ≤ 50%.

    This project aims to build erasure coding support as a first-class citizen in HDFS. By doing it will improve the performance, security, and robustness upon prior solutions including HDFS-RAID, as well as enable storage saving for a much wider range of workloads.

    See project

Honors & Awards

  • Outstanding Technical Achievement Award

    -

    For contributions in the Software License Management project.

Languages

  • Chinese

    Native or bilingual proficiency

  • English

    Full professional proficiency

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