failover

问题 I'm wondering how load balacing and failover between client and query routers work in MongoDB. I haven't found any matching documentation so far. Everyone says it's not relevant and I don't think so. Every piece of software / hardware can die and there'll be always a reason why you can't bring it up immediately again. The situation is very simple. Assuming a usual setup with sharded replicat sets, a client connects to a query router and performs operations. What happens if the query router

问题 Is there a way to programmatically determine which node in a SQL Server failover cluster is the active node ? Or at least determine whether the current machine is the active node? I have a Windows program which runs on both physical nodes in a failover cluster, but that should operate differently depending on whether it is running on the active node. Part of the reason is that this program should not run simultaneously on the inactive and the active node . (I've read a bit about making the

问题 I have a twisted ReconnectingClientFactory and i can successfully connect to given ip and port couple with this factory. And it works well. reactor.connectTCP(ip, port, myHandsomeReconnectingClientFactory) In this situation, when the server is gone, myHandsomeReconnectingClientFactory tries to connect same ip and port (as expected). My goal is, when the server which serves on given ip and port couple is gone, connecting to a backup server (which have different ip and port). Any ideas/comments

问题 I am looking for some initial pointers on how to cluster a ServiceMix solution. Basically what I need is: having 2 (or more) ServiceMix instances serving my routing needs and sharing the load if one instance fails, other(s) continue to serve if the failed one is brought back to life, it joins the party Searching for information confuses me since some references (eg. http://trenaman.blogspot.fi/2010/04/four-things-you-need-to-know-about-new.html) talk about "JBI cluster engine". I don't want

问题 We're currently using Redis 2.8.4 and StackExchange.Redis (and loving it) but don't have any sort of protection against hardware failures etc at the moment. I'm trying to get the solution working whereby we have master/slaves and sentinel monitoring but can't quite get there and I'm unable to find any real pointers after searching. So currently we have got this far: We have 3 redis servers and sentinel on each node (setup by the Linux guys): devredis01:6383 (master) devredis02:6383 (slave)

问题 I have been reading the docs and from my understanding I could see a scenario whereby a rollback could still occur: Write goes to primary which confirms that the journal has been written to disk Majority of the secondaries confirm the write but do not write to disk Power fails on entire cluster Primary for some reason does not start back up when power is restored A secondary takes the primary role The original primary finally starts, rejoins the set as a secondary and rolls back Is this

问题 I am trying to configure an Apache load balancing solution with mod_jk. The clustering works but not load balancing. I have Apache httpd 2.2 server running on my laptop. I have two VMWare Virtual Machine Guest Operating systems. All three are windows. The VMware machines hosts Apache Tomcat Server serving the web application. I have configured httpd.conf file with mod_jk and a workers properties file with the worker information. I am able to access my web application using the URL : http:/

问题 I am migrating my Database from MSSQL to Aurora(MYSQL). The application is using .net and NHibernate. We tried the Nhibernate driver for MYSQL "MySql.Data" and it works fine for all use cases but failover. When a failover happens, the connection is not reset and it keeps trying to connect to the old IP from the writer cluster and so all the write call fails with the exception "The MySQL server is running with the --read-- only option so it cannot execute this statement". This only gets

问题 In the context of a Docker setup, I want to use an ambassador-like pattern to allow some container (e.g., database server) to restart gracefully without having to restart all dependent containers (e.g., web server) and without error messages because "database server is not available". Therefore, I was wondering: Is there a TCP proxy software (that would run in the ambassador container) that can accept and hold connections if the backend is down and re-establish them when it is back? In the

问题 There are multiple articles suggesting that load-balancer should be used in front of RabbitMQ cluster. However, there are also multiple references that Spring AMQP is using some failover implementation like connection reset when broker comes back to life. I have several questions regarding this topic (given that those articles are more or less old and it's 2018 today) When using Spring AMQP, is it load-balancing for still required? If load-balancing is still suggested, how would I solve