From 0341825c858ddfddbda91d4493496884808bb1dc Mon Sep 17 00:00:00 2001 From: Peter Somogyi Date: Wed, 2 Aug 2017 17:00:52 +0200 Subject: [PATCH] HBASE-18504 Add documentation for WAL compression --- src/main/asciidoc/_chapters/architecture.adoc | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/main/asciidoc/_chapters/architecture.adoc b/src/main/asciidoc/_chapters/architecture.adoc index ebb06775ae..564337ceb2 100644 --- a/src/main/asciidoc/_chapters/architecture.adoc +++ b/src/main/asciidoc/_chapters/architecture.adoc @@ -1216,6 +1216,18 @@ This will be the default for HBase 0.99 (link:https://issues.apache.org/jira/bro You must also enable HFile version 3 (which is the default HFile format starting in HBase 0.99. See link:https://issues.apache.org/jira/browse/HBASE-10855[HBASE-10855]). Distributed log replay is unsafe for rolling upgrades. +[[wal.compression]] +==== WAL Compression ==== + +The content of the WAL can be compressed using LRU Dictionary compression. +This can be used to speed up WAL replication to different datanodes. +The dictionary can store up to 2^15^ elements; eviction starts after this number is exceeded. + +To enable WAL compression, set the `hbase.regionserver.wal.enablecompression` property to `true`. +The default value for this property is `false`. +By default, WAL tag compression is turned on when WAL compression is enabled. +You can turn off WAL tag compression by setting the `hbase.regionserver.wal.tags.enablecompression` property to 'false'. + [[wal.disable]] ==== Disabling the WAL -- 2.13.1