How to fix HBase 0.94.x not starting after downgrade

hbase_logo-470x140After downgrading my HBase installation from HBase 1.1.2 (currently stable at time of writing) to HBase 0.94.27, for purposes of compatibility with Gora I found myself unable to run HBase with multiple errors, after a couple of hours of debugging I found that the solution is to simply delete all the files in the hbase.rootdir which I specified in my hbase-site.xml

so, if your hbase-site.xml has the following properties

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<value> file:///home/hbuser/HBASE/hbase</value>



just cd to the previous directory and drop the hbase folder and recreated

cd /home/hbuser/HBASE
rm -Rf hbase
mkdir hbase

after this, just start hbase with and eveything should be fine.

Related Error Stacks:

org.apache.hadoop.hbase.master.HMaster: Unhandled exception. Starting shutdown.
at org.apache.hadoop.hbase.util.Bytes.toBytes(
org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /hbase/hbaseid