On 08/11/2010 06:49 PM, Adam Rosien wrote:
http://hadoop.apache.org/zookeeper/docs/r3.3.1/zookeeperAdmin.html#sc_dataFileManagement
says that one can copy the contents of the data directory and use it
on another machine. The example states the other instance is not in
the server list; what would happen if one did copy it to an offline
member of the quorum that then starts up?
The previously offline member will contact the quorum leader and see
that it has an older version of the db, it will then synchronize with
the leader as usual. (either by d/l a diff or if too bar behind getting
a full snapshot).
Do the docs imply that one can copy the data directory as-is as a
backup method? Is it restorable to any crashed/hosed server, or only
the one with the same server id?
It can be copied as is. Keep in mind though this is only needed for
catastrophic failures (the entire zk serving cluster is lost) - not the
case where a single server loses it's HD for example, in that case you
just restart the server - it will contact the leader and synchronize as
I detailed above.
What is a valid backup method for zk data?
Copy the datadirectory (snapshots and logs)
Patrick
