HBase

Notes on HBaseCon West 2017 presentations: 1. HBase at Xiaomi Presented jointly by Zhe Yang and Guanghao Zhang—both became HBase Committers in 2016 (Xiaomi has produced eight HBase Committers in total, including two PMC members, and has resolved hundreds of issues). Highlights included: Lessons from upgrading clusters from 0.94 to 0.98. Experience using G1GC for internal HBase deployments. Community contributions and improvements in 2016, including ordered replication log push, Scan optimizations, async client development, and related benchmark results....

In an HBase master-slave replication cluster, as shown on the left in the figure below, Region-Server-X and Region-Server-Y are two RegionServers in the master cluster. Under normal conditions, writes to Region-A append logs to Hlog-X on Region-Server-X, and Region-Server-X asynchronously applies those HLog entries in batches to the slave cluster. If Region-Server-X then crashes, Region-A is taken over by Region-Server-Y. Subsequent writes to Region-A append logs to Hlog-Y, while Region-Server-Y starts a new thread to replay Hlog-X....