Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.
- Create BookmarkCreate Bookmark
- Create Note or TagCreate Note or Tag
- DownloadDownload
- PrintPrint
HDFS > Persistent Data Structures
Persistent Data Structures
As an administrator, it is invaluable to have a basic understanding of how the components of HDFS—the namenode, the secondary namenode, and the datanodes—organize their persistent data on disk. Knowing which files are which can help you diagnose problems or spot that something is awry.
A newly formatted namenode creates the following directory structure:
${dfs.name.dir}/current/VERSION
/edits
/fsimage
/fstime
Recall from Chapter 9 that the dfs.name.dir property is a list of
directories, with the same contents mirrored in each directory. This
mechanism provides resilience, particularly if one of the
directories is an NFS mount, as is recommended.
