On Mon, Jul 2, 2012 at 7:37 PM, Bryan Keller <brya...@gmail.com> wrote: > During an upgrade of my cluster to 0.90 to 0.92 over the weekend, the WAL > (files in the /hbase/.logs directory) was corrupted and it prevented HBase > from starting up. The exact exception was "java.io.IOException: Could not > obtain the last block locations" on the WAL files. >
Next time, run hdfs fsck and see what it says about your WALs. > I was able to recover by deleting the /hbase/.logs directory. My question is, > if HBase had no pending updates, i.e. nothing writing to it, is there any > risk of data loss by deleting the WAL directory? For example, does > rebalancing, flushing, or compaction use the WAL or is the WAL used only for > inserts/updates/deletes? Only by inserts, etc. You could have lost data if edits were in memory on regionserver only and they had not yet been flushed. St.Ack
