HBase Common Errors and Solutions

 

1. RegionServer Out of Memory (OOM)

Error Message:

java.lang.OutOfMemoryError: Java heap space

Cause:

• Insufficient heap size for RegionServer.
• Too many regions on a single RegionServer.
• Heavy compaction or memstore flush operations.

Solution:

1. Increase heap size in hbase-env.sh:

   export HBASE_HEAPSIZE=8G
   

2. Distribute regions across multiple RegionServers.
3. Tune compaction settings in hbase-site.xml:

   <property>
       <name>hbase.hstore.compactionThreshold</name>
       <value>5</value>
   </property>
   

---

2. HMaster Not Starting

Error Message:

org.apache.hadoop.hbase.master.HMaster: Failed to become active master

Cause:

• Another active master is already running.
• Zookeeper connectivity issue.

Solution:

1. Check if another master is running:

   echo stat | nc localhost 2181
   

2. If stuck, manually remove old master Znode:

   echo "rmr /hbase/master" | hbase zkcli
   

3. Restart HMaster:

   hbase-daemon.sh start master
   

---

3. RegionServer Connection Refused

Error Message:

java.net.ConnectException: Connection refused

Cause:

• RegionServer process is down.
• Incorrect hostname or firewall issues.

Solution:

1. Restart RegionServer:

   hbase-daemon.sh start regionserver
   

2. Check firewall settings:

   iptables -L
   

3. Verify correct hostname in hbase-site.xml.

---

4. RegionServer Crashes Due to Too Many Open Files

Error Message:

Too many open files

Cause:

• File descriptor limits are too low.

Solution:

1. Increase file descriptor limits:

   ulimit -n 100000
   

2. Update /etc/security/limits.conf:

   hbase soft nofile 100000
   hbase hard nofile 100000
   

---

5. HBase Table Stuck in Transition

Error Message:

Regions in transition: <table-name> stuck in transition

Cause:

• Region assignment failure.
• Split or merge operation issues.

Solution:

1. List regions in transition:

   hbase hbck -details
   

2. Try to assign the region manually:

   hbase shell
   assign 'region-name'
   

3. If stuck, use hbck2 tool to recover:

   hbase hbck2 fixMeta