Index: src/docbkx/book.xml
===================================================================
--- src/docbkx/book.xml (revision 1214613)
+++ src/docbkx/book.xml (working copy)
@@ -1319,6 +1319,8 @@
Startup Sequencing
The META location is set in ROOT first. Then META is updated with server and startcode values.
+ For information on region-RegionServer assignment, see .
+
@@ -1724,46 +1726,35 @@
Startup
When HBase starts regions are assigned as follows (short version):
-
-
- The Master invokes the AssignmentManager upon startup.
+ The Master invokes the AssignmentManager upon startup.
-
- The AssignmentManager looks at the existing region assignments
- in META.
+ The AssignmentManager looks at the existing region assignments in META.
-
- If the region assignment is still valid (i.e., if the RegionServer) is still online
+ If the region assignment is still valid (i.e., if the RegionServer) is still online
then the assignment is kept.
-
-
- If the assignment is invalid, then the LoadBalancerFactory is invoked to assign the
- region. The DefaultLoadBalancer will randomly assign the region to a RegionServer.
-
+ If the assignment is invalid, then the LoadBalancerFactory is invoked to assign the
+ region. The DefaultLoadBalancer will randomly assign the region to a RegionServer and
+ update META.
-
-
+
+
Failover
When a RegionServer fails (short version):
-
-
- The regions immediately become unavailable because the RegionServer is down.
+ The regions immediately become unavailable because the RegionServer is down.
-
- The Master will detect that the RegionServer has failed.
+ The Master will detect that the RegionServer has failed.
-
- The region assignments will be considered invalid and will be re-assigned just
+ The region assignments will be considered invalid and will be re-assigned just
like the startup sequence.
-
+
@@ -1784,9 +1775,9 @@
First replica is written to local node
- Second replica to another node in same rack
+ Second replica is written to another node in same rack
- Third replica to a node in another rack (if sufficient nodes)
+ Third replica is written to a node in another rack (if sufficient nodes)
HBase eventually achieves locality for a region after a flush a compaction.