1. The namenode webpage shows: Upgrades: Upgrade for version -18 has been completed. Upgrade is not finalized.
2. SequenceFile.Writer failed when trying to creating a new file with the following error: (we have two HaDoop clusters, both have issue 1; one has issue 2, but the other is fine on issue 2). Any idea what's going on? Thanks, -Songting java.io.IOException: Filesystem closed at org.apache.hadoop.hdfs.DFSClient.checkOpen(DFSClient.java:198) at org.apache.hadoop.hdfs.DFSClient.access$600(DFSClient.java:65) at org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.closeInternal(DFSClient.java:3084) at org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.close(DFSClient.java:3053) at org.apache.hadoop.hdfs.DFSClient$LeaseChecker.close(DFSClient.java:942) at org.apache.hadoop.hdfs.DFSClient.close(DFSClient.java:210) at org.apache.hadoop.hdfs.DistributedFileSystem.close(DistributedFileSystem.java:243) at org.apache.hadoop.fs.FileSystem$Cache.closeAll(FileSystem.java:1413) at org.apache.hadoop.fs.FileSystem.closeAll(FileSystem.java:236) at org.apache.hadoop.fs.FileSystem$ClientFinalizer.run(FileSystem.java:221)