From ff53d753301dc4d813f58efb0422552f13b43e7f Mon Sep 17 00:00:00 2001 From: Michael Stack Date: Wed, 22 Jan 2014 00:39:57 +0000 Subject: [PATCH] Edit of SlabCache note git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1560228 13f79535-47bb-0310-9956-ffa450edef68 --- src/main/docbkx/upgrading.xml | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/src/main/docbkx/upgrading.xml b/src/main/docbkx/upgrading.xml index 869a44d9d87..23e6e2e4848 100644 --- a/src/main/docbkx/upgrading.xml +++ b/src/main/docbkx/upgrading.xml @@ -333,13 +333,14 @@ The block size default size has been changed in 0.92.0 from 0.2 (20 percent of h -
Experimental off-heap cache - +
Experimental off-heap cache: SlabCache A new cache was contributed to 0.92.0 to act as a solution between using the “on-heap” cache which is the current LRU cache the region servers have and the operating system cache which is out of our control. -To enable, set “-XX:MaxDirectMemorySize” in hbase-env.sh to the value for maximum direct memory size and specify hbase.offheapcache.percentage in hbase-site.xml with the percentage that you want to dedicate to off-heap cache. This should only be set for servers and not for clients. Use at your own risk. -See this blog post for additional information on this new experimental feature: http://www.cloudera.com/blog/2012/01/caching-in-hbase-slabcache/ +To enable SlabCache, as this feature is being called, set “-XX:MaxDirectMemorySize” in hbase-env.sh to the value for maximum direct memory size and specify +hbase.offheapcache.percentage in hbase-site.xml with the percentage that you want to dedicate to off-heap cache. This should only be set for servers and not for clients. Use at your own risk. +See this blog post, Caching in Apache HBase: SlabCache, for additional information on this new experimental feature. +This feature has mostly been eclipsed in later HBases. See HBASE-7404 Bucket Cache:A solution about CMS,Heap Fragment and Big Cache on HBASE, etc.
Changes in HBase replication