As part of our experimentation, the plan is to pull 4 slave nodes out of a
8-slave/1-master cluster. With replication factor set to 3, I thought
losing half of the cluster may be too much for hdfs to recover. Thus I
copied out all relevant data from hdfs to local disk and reconfigure the
cluster.
The 4 slave nodes started okay but hdfs never left safe mode. The nn.log
has the following line. What is the best way to deal with this? Shall I
restart the cluster with 8-node and then delete
/data/hadoop-hadoop/mapred/system? Or shall I reformat hdfs?
Thanks.
2010-08-05 22:28:12,921 INFO
org.apache.hadoop.hdfs.server.namenode.FSNamesystem.audit:
ugi=hadoop,hadoop ip=/10.128.135.100 cmd=listStatus
src=/data/hadoop-hadoop/mapred/system dst=null perm=null
2010-08-05 22:28:12,923 INFO org.apache.hadoop.ipc.Server: IPC Server
handler 0 on 9000, call delete(/data/hadoop-hadoop/mapred/system, true) from
10.128.135.100:52368: error:
org.apache.hadoop.hdfs.server.namenode.SafeModeException: Cannot delete
/data/hadoop-hadoop/mapred/system. Name node is in safe mode.
The reported blocks 64 needs additional 3 blocks to reach the threshold
0.9990 of total blocks 68. Safe mode will be turned off automatically.
org.apache.hadoop.hdfs.server.namenode.SafeModeException: Cannot delete
/data/hadoop-hadoop/mapred/system. Name node is in safe mode.
The reported blocks 64 needs additional 3 blocks to reach the threshold
0.9990 of total blocks 68. Safe mode will be turned off automatically.
at
org.apache.hadoop.hdfs.server.namenode.FSNamesystem.deleteInternal(FSNamesystem.java:1741)
at
org.apache.hadoop.hdfs.server.namenode.FSNamesystem.delete(FSNamesystem.java:1721)
at
org.apache.hadoop.hdfs.server.namenode.NameNode.delete(NameNode.java:565)
at sun.reflect.GeneratedMethodAccessor13.invoke(Unknown Source)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:512)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:968)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:964)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:962)
