[jira] [Created] (HBASE-10278) Provide better write predictability

["Himanshu Vashishtha (JIRA)" <ji...@apache.org>]

Himanshu Vashishtha created HBASE-10278:
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             Summary: Provide better write predictability
                 Key: HBASE-10278
                 URL: https://issues.apache.org/jira/browse/HBASE-10278
             Project: HBase
          Issue Type: New Feature
            Reporter: Himanshu Vashishtha


Currently, HBase has one WAL per region server. 
Whenever there is any latency in the write pipeline (due to whatever reasons such as n/w blip, a node in the pipeline having a bad disk, etc), the overall write latency suffers. 

Jonathan Hsieh and I analyzed various approaches to tackle this issue. We also looked at HBASE-5699, which talks about adding concurrent multi WALs. Along with performance numbers, we also focussed on design simplicity, minimum impact on MTTR & Replication, and compatibility with 0.96 and 0.98. Considering all these parameters, we propose a new HLog implementation with WAL Switching functionality.

Please find attached the design doc for the same. It introduces the WAL Switching feature, and experiments/results of a prototype implementation, showing the benefits of this feature.
The second goal of this work is to serve as a building block for concurrent multiple WALs feature.

Please review the doc.



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