diff --git a/src/main/docbkx/performance.xml b/src/main/docbkx/performance.xml index 0e2c5305332..174baf2b2fb 100644 --- a/src/main/docbkx/performance.xml +++ b/src/main/docbkx/performance.xml @@ -726,8 +726,9 @@ configurations. dfs.client.read.shortcircuit.buffer.size - The default for this value is too high when running on a highly trafficed HBase. Set it down from its - 1M default down to 128k or so. Put this configuration in the HBase configs (its a HDFS client-side configuration). + The default for this value is too high when running on a highly trafficed HBase. + In HBase, if this value has not been set, we set it down from the default of 1M to 128k + (Since HBase 0.98.0 and 0.96.1). See HBASE-8143 HBase on Hadoop 2 with local short circuit reads (ssr) causes OOM). The Hadoop DFSClient in HBase will allocate a direct byte buffer of this size for each block it has open; given HBase keeps its HDFS files open all the time, this can add up quickly.