Thanks Marcel. What we are looking for is nowhere near as elegant of a solution as you've outlined below. Quoting the same page as David, we are most interested in
"Messages which are published are sent to all masters." Because we really just want a second master node that stays in sync with the primary master. In our scenario we don't need any type of smart failover or load balancing, we want to make sure that 2 nodes are receiving and persisting the same information. In normal usage, the primary node will always receive messages. In a catastrophic situation where the primary node fails (hardware error, etc) we need to be able to switch to the secondary node that should be in sync with the primary, and manual reconfiguration is acceptable. So from your mail below, I take it that persisting at 2 nodes is not implemented yet? If not, it sounds like you recommend mirroring at the database level? Thanks, Craig -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Marcel Ruff Sent: Tuesday, December 08, 2009 4:41 AM To: [email protected] Subject: Re: [xmlblaster] Mirrored Masters? Hi David, multi master is not implemented. The I_LoadBalancer#getClusterNode() returns one node (NodeMasterInfo) which is used to forward messages to the next node, but only to one. If you need mirroring you could, depending if you need "failover" or "load balancing", consider following: 1) Change the xmlBlaster cluster code to handle multiple masters You need to decide in this case if the multiple masters are informed in a transaction (sync) or not (async). Clients need to be coded to choose a master depending on current load or failure. -> failover and load balancing 2) You could create an extended I_Queue and I_Map plugin which duplicates the data to two DBs -> failover 3) You could do low-level DB mirroring (DRDB, Linux HA et al) xmlBlaster gets on startup all information to re-establish its state. In this case the mirrored xmlBlaster is started on failure of the first, clients automatically find the mirrored as the IP is change (standard HA behaviour) -> failover 4) Master/Slave operation (exists already, one master with many salves) -> load balancing 5) Combination of 3) and 4) should work out of the box -> failover and load balancing It depends on what you want to achieve, best regards Michele Marcel David R Robison schrieb: > In the discussion on clustering in the reference manual it talks about > mirrored masters: > > /An xmlBlaster cluster allows to have more than one master server > for a specific message domain. The master nodes are //mirrored > instances for those messages. Published messages reach all master > nodes. Subscribed messages are retrieved using a load balance > algorithm. > / > > > However, the discussion says that it has not been implemented. Has any > work been done on this? Any suggestions on how to achieve this? > Thanks, David > -- > > David R Robison > Open Roads Consulting, Inc. > 103 Watson Road, Chesapeake, VA 23320 > phone: (757) 546-3401 > e-mail: [email protected] > web: http://openroadsconsulting.com > blog: http://therobe.blogspot.com > book: http://www.xulonpress.com/bookstore/bookdetail.php?PB_ISBN=9781597816526 > > This e-mail communication (including any attachments) may contain > confidential and/or privileged material intended solely for the individual or > entity to which it is addressed. If you are not the intended recipient, you > should immediately stop reading this message and delete it from all computers > that it resides on. Any unauthorized reading, distribution, copying or other > use of this communication (or its attachments) is strictly prohibited. If > you have received this communication in error, please notify us immediately. > -- Marcel Ruff http://www.xmlBlaster.org http://watchee.net Phone: +49 7551 309371
