You can start HDFS without finalizing the upgrade. When you are ready to discard your backup, you can finalize the upgrade.
![[Warning]](../common/images/admon/warning.png) | Warning |
|---|---|
You must verify your filesystem health before finalizing the upgrade. After you finalize an upgrade, you cannot roll back. |
To finalize the upgrade process, run the following command as the $HDFS_USER:
hadoop dfsadmin -finalizeUpgrade
