"Jürgen Link" <juergen.l...@googlemail.com> wrote: >Hi all, >I successfully did set up a tomcat cluster (3 nodes) with session >replication, using the standard DeltaManager. > >In order to allow for more nodes, I'd like to switch to BackupManager >for >primary-secondary replication on a dedicated backup node. >Unfortunately, the official documentation (and various other sources >out >there) simply states "For larger clusters, to use a primary-secondary >session replication where the session will only be stored at one backup >server simply setup the BackupManager". >I therefore tried to replace DeltaManager in all node's three >context.xml by >BackupManager, but sessions still get replicated on all three nodes. >I also tried to configure only one node with BackupManager, but it >didn't >help either. > >I'm obviously missing something - can someone give a sketch of how to >configure the cluster correctly?
The backup manager doesn't work the way you think it does. Consider a four node cluster with nodes A, B, C & D. If node A has 30 primary sessions (more on that on a sec) then 10 of them will be backed up on node B, 10 on node C and 10 on node D. Sessions may be primary (currently being used), backup (full copy of the primary) or proxy (no data but knows which nodes are primary and backup). If a node isn't the primary or a backup it will be a proxy. You have to use sticky sessions with the backup manager else the primary node for the session keeps changing and that creates a lot of traffic. If the primary node fails, any other node can take over since they all have either a backup or the proxy info. Mark --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
