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Mahadev konar commented on ZOOKEEPER-1016: ------------------------------------------ Couple of reasons I have been thinking abt this. Having filesystem view will ease up the complexity in transactional logging where I am certain things like this would come handy: 1) manipulating directories to find last updated files 2) grep through the files (filesystem reg ex implementations will come in handy) 3) for debuggability - hadoop dfs -cat bk://txnfilename | decoder (in case its binary) to take a look at the last logs will come in handy as well. > TeaKeeper: Hot standby support using bookkeeper > ----------------------------------------------- > > Key: ZOOKEEPER-1016 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-1016 > Project: ZooKeeper > Issue Type: Improvement > Reporter: Ivan Kelly > Assignee: Ivan Kelly > Priority: Minor > Attachments: tledger.pdf, tledger.pdf > > > Currently Bookkeeper provides functionality for cold backups. If the entity > logging to bookkeeper fails, its replacement must recover the ledgers which > had been used for backup before becoming available. This is acceptable in > some cases, such as HBase Wals where a small delay in recovery only results > in a small percentage of data being unavailable. > However, systems such as the HDFS namenode, this delay can be unacceptable, > such as cases where data is being served to customers. Secondary namenodes > should be ready to go the instant the primary goes down. > TeaKeeper proposes a wrapper library around Bookkeeper providing T-Junction > like functionality for logging. It also provides for primary/secondary > election and automated hot failover. > HDFS namenode is primary target of this work. > The attached design doc contains more details. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira