Configuring HBase MultiWAL

You can configure multiple write-ahead logs (MultiWAL) for HBase. If you do not configure MultiWAL, each region on a RegionServer writes to the same WAL.

A busy RegionServer might host several regions, and each write to the WAL is serial because HDFS only supports sequentially written files. This causes the WAL to negatively impact performance.

MultiWAL allows a RegionServer to write multiple WAL streams in parallel by using multiple pipelines in the underlying HDFS instance, which increases total throughput during writes.

To configure MultiWAL for a RegionServer, set the value of the property hbase.wal.provider to multiwal and restart the RegionServer. To disable MultiWAL for a RegionServer, unset the property and restart the RegionServer.

RegionServers using the original WAL implementation and those using the MultiWAL implementation can each handle recovery of either set of WALs, so a zero-downtime configuration update is possible through a rolling restart.