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Ivan Kelly commented on ZOOKEEPER-1016: --------------------------------------- Added a new design doc. Focus has changes from creating a T to providing transaction id and named ledger support. Streaming has been removed for the moment. The content and api has changed completely, so its worth taking another look even if you've read the previous version. > 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