In shell is a move command. You can also force running of balancer (or even turn it off).
For how the balancer works, in short, it runs every 5 minutes by default (configurable) and when it runs, using its in-memory notion of how the cluster is balanced, creates move plans that are immediately acted upon on balance calculation completion. Current balancer aims to keep the load of regions even across the cluster. If you would like to know more beyond whats written above, next up would be the LoadBalancer classes javadoc: http://hbase.apache.org/xref/org/apache/hadoop/hbase/master/LoadBalancer.html#42 Its not bad. Check it out. St.Ack On Wed, Feb 2, 2011 at 7:51 PM, Wayne <wav...@gmail.com> wrote: > I know there were some changes in .90 in terms of how region balancing > occurs. Is there a resource somewhere that describes the options for the > configuration? Per Jonathan Gray's recommendation we are trying to keep our > region count down to 100 per region server (we are up to 5gb region size). > This has caused us to get a lot of hot spots relative to what we saw with > 1000 regions per node. Scanning through #3373 it sounded like there is a > round-robin load balancer we can turn on instead of keeping regions pinned > as I believe they are in .90 by default. We have many tables and certain > region servers seem to get "stuck" with a single table's data in almost > contiguous ranges which really throws a wrench in our load balancing. > > Thanks. >
