failover

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 dies? Is there an intended way for automatic failover to a second query router? Or for load balancing

I'm currently developing a project supported on a WebLogic clustered environment. I've successfully set up the cluster, but now I want a load-balancing solution (currently, only for testing purposes, I'm using WebLogic's HttpClusterServlet with round-robin load-balancing). Is there any documentation that gives a clear comparison (with pros and cons) of the various ways of providing load-balancing for WebLogic? These are the main topics I want to cover: Performance (normal and on failover ); What failures can be detected and how fast is the failover recovery; Transparency to failure (e.g.,

Closed . This question needs to be more focused. It is not currently accepting answers. Learn more . Want to improve this question? Update the question so it focuses on one problem only by editing this post . What's the difference between failover and disaster recovery? Vinko Vrsalovic Failover: When one machine fails, another machine (usually in the same location) takes over and resumes service Disaster recovery: When Godzilla destroys your data center, you do have alternative locations to keep providing your service and protocols/means for the other location to know how to keep delivering

Here's my scenario (designed by my predecessor): Two Apache servers serving reverse proxy duty for a number of mixed backend web servers (Apache, IIS, Tomcat, etc.). There are some sites for which we have multiple backend web servers, and in those cases, we do something like: <Proxy balancer://www.example.com> BalancerMember http://192.168.1.40:80 BalancerMember http://192.168.1.41:80 </Proxy> <VirtualHost *:80> ServerName www.example.com:80 CustomLog /var/log/apache2/www.example.com.log combined <Location /> Order allow,deny Allow from all ProxyPass balancer://www.example.com/

I am trying to create a Redis message bus failover scenario with a SignalR app. At first, we tried a simple hardware load-balancer failover, that simply monitored two Redis servers. The SignalR application pointed to the singular HLB endpoint. I then failed one server, but was unable to successfully get any messages through on the second Redis server without recycling the SignalR app pool. Presumably this is because it needs to issue the setup commands to the new Redis message bus. As of SignalR RC1, Microsoft.AspNet.SignalR.Redis.RedisMessageBus uses Booksleeve's RedisConnection() to connect

I'm planning on making a distributed database system using a shared-nothing architecture and multiversion concurrency control . Redundancy will be achieved through asynchronous replication (it's allowed to lose some recent changes in case of a failure, as long as the data in the system remains consistent). For each database entry, one node has the master copy (only that node has write access to it), in addition to which one or more nodes have secondary copies of the entry for scalability and redundancy purposes (the secondary copies are read-only). When the master copy of an entry is updated,