pure master slave is handy for data replication but is lock step rather than catch up, is limited to a single pair and has no auto recovery strategy.
Master slave with a shared file system or shared database is what you want for fault tolerance. The first to obtain a lock is a master and the next to acquire the lock will assume mastership in the event of failure. This setup along with the failover transport will give you a simple and reliable fault tolerant solution. 2009/7/29 Norbert Pfistner <npfist...@picturesafe.de> > We also plan to use master/slave. > > The 'waitForSlave' seems a bit strange for me, since our main reason for > adding some slaves is to avoid a single point of failure (i.e. the master). > But what if the slave fails? Does the required 'waitForSlave' mean that we > can't run a master without his slaves? Doesn't this even increase the risk > of failure? > > In an ideal world i would expect that using master slave would meen simply > start a borker (first will be the master), add any slaves you want (which > should be configured by the clients) any time later and beeing able to > indipendly start/stop/crash one of them: The whole messaging system should > remain stable as long at least one broker is up. > > Is this possible with activeMQ? Which version should we use (currently we > use 5.2, not yet in Master/Slave, JDBC persistance). > > Are there any special settings we need to set to achieve the goal discribed > above? > > Greetings, > Norbert > > brendanr schrieb: > > Thank you for your reply. >> I know about the 'waitForSlave' attribute, but it is not really what I >> need. >> I would like to be able to add a backup machine (and hence a slave broker) >> at some later time, without having to restart the master broker and all >> the >> producer/consumer connections to it. I would have expected that when a >> slave >> connected that it could learn about all messages/producers/consumers >> connected to the master, and continue operating correctly. >> >> But from what you are saying, this is not possible? Will it be available >> when the Kaha DB feature is available? >> Many thanks again. >> >> Gary Tully wrote: >> >>> the brokers need to be in sync from the start. there is a waitForSlave >>> attribute that can force the master to stall till the slave connects. >>> see: >>> https://issues.apache.org/activemq/browse/AMQ-596 >>> >>> 2009/7/29 brendanr <brendan.rona...@gmail.com> >>> >>> Hi, >>>> >>>> I am having an issue with a simple master/slave setup. My master is >>>> running >>>> on one machine (192.168.10.141), and my slave is running on a separate >>>> machine (192.168.10.1). Attached are the config files for both master >>>> and >>>> slave, and the log files for master and slave. I am running broker >>>> version >>>> 5.2.0 and using activemq CPP library 3.0.1. My producer and consumers >>>> are >>>> using the supplied sample code. >>>> >>>> On the master broker I get an exception saying the following: >>>> ERROR MasterBroker - Slave Failed: ... >>>> On the slave broker I get an exception daying teh following: >>>> ERROR Service - Async error occurred: ... >>>> >>>> Please see attached log files for complete exceptions. >>>> >>>> I can easily reproduce the errors under the following conditions: >>>> 1. Start the master broker >>>> 2. Start a producer that connects to the master broker and sends 10 >>>> messages >>>> to queue TEST.FOO. Producer disconnects. >>>> 3. Start the slave broker. It connects to teh master broker >>>> successfully. >>>> 3. Start a consumer that connects to the master broker. It will retrieve >>>> the >>>> messages successfuly, but will cause the exceptions on both brokers. >>>> >>>> It doesn't matter if the producer and consumer connect to the broker >>>> using >>>> the failover mechanism (using 2 addresses) or not. >>>> If I start both brokers first, before connecting any producers/consumers >>>> then I do not get the exceptions, but in the application I would like to >>>> use >>>> activemq in, it is not unreasonable that the master broker will have >>>> some >>>> activity before the slave broker is ready to connect. >>>> >>>> Should activemq work the way I would like it to work, and if so what am >>>> I >>>> doing wrong? Any help would be much appreciated. >>>> >>>> Thanks >>>> Brendan >>>> >>>> >>>> >>>> http://www.nabble.com/file/p24716703/activemq-master.logactivemq-master.log >>>> >>>> http://www.nabble.com/file/p24716703/activemq-master.xmlactivemq-master.xml >>>> http://www.nabble.com/file/p24716703/activemq-slave.log >>>> activemq-slave.log >>>> http://www.nabble.com/file/p24716703/activemq-slave.xml >>>> activemq-slave.xml >>>> -- >>>> View this message in context: >>>> >>>> http://www.nabble.com/Master-Slave%3A-Slave-Failed%2C-async-error-occurred-tp24716703p24716703.html >>>> Sent from the ActiveMQ - User mailing list archive at Nabble.com. >>>> >>>> >>>> >>> -- >>> http://blog.garytully.com >>> >>> Open Source Integration >>> http://fusesource.com >>> >>> >>> >> > -- > > Dipl.-Ing. Norbert Pfistner > Softwareentwicklung > > picturesafe GmbH > Simon-von-Utrecht-Straße 31-37 > D-20359 Hamburg > http://www.picturesafe.de > > fon: +49 40 374127 901 > fax: +49 40 374127 999 > npfist...@picturesafe.de > > Sitz der Gesellschaft: Hannover > Geschäftsführer: Herbert Wirth > HR: Amtsgericht Hannover HR B 53 366 > -- http://blog.garytully.com Open Source Integration http://fusesource.com
