[ https://issues.apache.org/jira/browse/HDFS-2001?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Todd Lipcon updated HDFS-2001: ------------------------------ Component/s: name-node Description: In the old design for edits/image storage, the secondary namenode does a complicated dance of moving "current/" to "lastcheckpoint.tmp", checkpointing into "current/", then moving "lastcheckpoint.tmp" back to "previous.checkpoint". The idea here was so that there would always be one directory with a valid set of storage files. In the HDFS-1073 design, this complicated dance isn't necessary. If a checkpoint fails, we can just rm that single fsimage_N.ckpt file and still be left with a valid storage directory. So, we can just let the 2NN keep a single current/ dir around for all checkpoints and eliminate the complexity of the dance. Affects Version/s: Edit log branch (HDFS-1073) Fix Version/s: Edit log branch (HDFS-1073) > HDFS-1073: Kill previous.checkpoint, lastcheckpoint.tmp directories > ------------------------------------------------------------------- > > Key: HDFS-2001 > URL: https://issues.apache.org/jira/browse/HDFS-2001 > Project: Hadoop HDFS > Issue Type: Sub-task > Components: name-node > Affects Versions: Edit log branch (HDFS-1073) > Reporter: Todd Lipcon > Assignee: Todd Lipcon > Fix For: Edit log branch (HDFS-1073) > > > In the old design for edits/image storage, the secondary namenode does a > complicated dance of moving "current/" to "lastcheckpoint.tmp", checkpointing > into "current/", then moving "lastcheckpoint.tmp" back to > "previous.checkpoint". The idea here was so that there would always be one > directory with a valid set of storage files. > In the HDFS-1073 design, this complicated dance isn't necessary. If a > checkpoint fails, we can just rm that single fsimage_N.ckpt file and still be > left with a valid storage directory. > So, we can just let the 2NN keep a single current/ dir around for all > checkpoints and eliminate the complexity of the dance. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira