>> Which confuses me, if the write goes straight to a RegionServer, but >> then the RegionServer fails before the MemStore is flushed, did I just >> lose data? > > No that's the goal of the write-ahead-log (WAL).
Here's the scenario I just tested on my EC2 cluster. 3 Zookeeper instances, 1 master, and 3 slaves. I created a table, and inserted a single row. I performed a read (get) to test the insert, and sure enough the row was returned. I then noted which slave held the table, and terminated the slave via the AWS management console. I then waited approx 30 seconds. I used the web interfaces (port 60030 and 60010) to note that the region was indeed moved to another slave. I performed a read on the same row, but did *not* find the row. So it looks like the region for the table was moved, but no data was moved over. Was that a valid test? I would expect the row to get moved with the region. Thanks, Seth
