@mike_bronson7 Let me try to answer all your 3 questions in a shot [snapshot] Zookeeper has 2 types of logs the snapshot and transactional log files. As changes are made to the znodes i.e addition or deletion of znodes these changes are appended to a transaction log, occasionally, when a log grows large, a snapshot of the current state of all znodes will be written to the filesystem. This snapshot supersedes all previous logs. To put you in context it's like the edit-logs and the fsimage in Namenode architecture, all changes made in the HDFS is logged in the edits-logs in secondary Namenode when a checkpoint kick in it merges the edits log with the old fsimage to incorporate the changes ever since the last checkpoint. So zk snapshot is synonym to the fsimage as it contains the current state of the znode entries and ACL's Snapshot policy In the earlier command shared the snapshot count parameter -n <count> if you really want to have sleep then you can increment it to 5 or 7 but I think 3 suffice to use the autopurge feature so I keep only 3 snapshots and 3 transaction logs. When enabled, ZooKeeper auto-purge feature retains the autopurge.snapRetainCount most recent snapshots and the corresponding transaction logs in the dataDir and dataLogDir respectively and deletes the rest. Defaults to 3. The minimum value is 3. Corrupt snapshots The Zookeeper might not be able to read its database and fail to come up because of some file corruption in the transaction logs of the ZooKeeper server. You will see some IOException on loading the ZooKeeper database. In such a case, make sure all the other servers in your ensemble are up and working. Use the 4 letters command "stat" command on the command port to see if they are in good health. After you have verified that all the other servers of the ensemble are up, you can go ahead and clean the database of the corrupt server. Solution Delete all the files in datadir/version-2 and datalogdir/version-2/. Restart the server. Hope that helps
... View more
