When a HBase Master believes a RegionServer is dead, the first step in recovering impacted regions[1] is to take over the HDFS leases of its WAL files. This prevents the RegionServer from continuing to accept edits and will cause it to abort once it sees the lease is gone.
[1]: http://hbase.apache.org/book.html#_wal_splitting On Wed, Oct 18, 2017 at 9:56 AM, Nikita Marshalkin <[email protected]> wrote: > Hi, > > I've got a question about HBase consistency guarantees, > especially linearizability, > and can't find the answer in the documentation. > > Consider the following scenario: > > 1. There is a network split between RegionServer and (Zookeeper and Master) > 2. Master reassigns region to another RegionServer > 3. Region hasn't reacted yet to ZK session expiration and still believes > that he is in game > > Now there are two RegionServers that think they are "the right one" > > Clients with outdated cache are communicating with the failed one, while > others are writing to the new one. > It violates assumption "single RegionServer for a region" > > What am I missing? > -- > Yours sincerely, > Nikita Marshalkin.
