Hadoop O & M-NameNode restart

Operation Procedure (proceed with caution and double check !!!)

1. Back up the current directory of the master node

2. Execute./Hadoop-daemon.sh start namenode-checkpoint on second namenode

3. Wait 30-40 minutes until the checkpoint is complete. Check the fsimage modification time of the current file on the master node to check whether the synchronization is successful.

Then execute./hadoop-daemon.sh stop namenode, stop second Namenode

4. Modify the hadoop-env.sh file under the conf directory of the master node and modify the JVM parameters. Make lab and computation estimates in advance.

5. Execute./hadoop-daemon.sh stop namenode on the master node, if not, kill-9 PID

6. Restart NameNode./The hadoop-daemon.sh start namenode

1) load the metadata file fsimage (~ 10 min)

2). Load the operation log edits (1 ~ 2 min)

3). store metadata to fsimage (3 ~ 4 min)

7. view the nameNode log and wait for the block report to be completed (10 ~ 15 min)

8. Manually trigger a Full GC to recycle the temporary objects in the old zone during the restart process.

9. After the service is normal, sending an email indicates that the cluster is back to normal

10. Observe the GC status of the mail report on a regular basis.

Tracking

Time	Reason	Priority	Importance	Desc.	Befor GC	After GC	Handled	Feedback

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