guyuqi commented on PR #913: URL: https://github.com/apache/bigtop/pull/913#issuecomment-1156060230
@iwasakims Thanks for your comments. Just as you mentioned, users could overwrite the existing fsimage by `hdfs namenode -format -force` or `-upgrade`, but not all new comers would know how to handle it when the issues occurred like: ``` Failed to start namenode. java.io.IOException: File system image contains an old layout version -63. An upgrade to version -65 is required. ..... ... ``` Hdfs is the distributed file system to make data safe. `Data replication `and `secondarynamenode` would help recover one node from the other nodes of the same cluster if fsimage and edit files were deleted. (Is it really dangerous?) From my perspective, if users remove(`$1 = 0` here, not upgrade) the Hadoop packages from one node, it seems there is no necessary to retain the deprecated data. On the other hand, it's convennient for users to deployment different Hadoop verisons by Mpack (or other automatic deployment tools) if we removed deprecated Hadoop fs-image after RPM/deb uninstallation. Is it the institutionalized acceptance that we don't touch `/hadoop/hdfs` even if there would be a obstacle to new comers? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
