Index: src/docbkx/book.xml =================================================================== --- src/docbkx/book.xml (revision 1243533) +++ src/docbkx/book.xml (working copy) @@ -1378,6 +1378,9 @@ the client will requery the catalog tables to determine the new location of the user region. + See for more information about the impact of the Master on HBase Client + communication. + Administrative functions are handled through HBaseAdmin
Connections @@ -1661,6 +1664,15 @@ take over the Master role.
+
Runtime Impact + A common dist-list question is what happens to an HBase cluster when the Master goes down. Because the + HBase client talks directly to the RegionServers, the cluster can still function in a "steady + state." Additionally, per ROOT and META exist as HBase tables (i.e., are + not resident in the Master). However, the Master controls critical functions such as RegionServer failover and + completing region splits. So while the cluster can still run for a time without the Master, + the Master should be restarted as soon as possible. + +
Interface The methods exposed by HMasterInterface are primarily metadata-oriented methods: