Invalidating cache due to ioctl

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Important You can invalidate most types of content that are served by a web distribution, but you cannot invalidate media files in the Microsoft Smooth Streaming format when you have enabled Smooth Streaming for the corresponding cache behavior.

Most our customer deployment are clusters they always need high availability and sometimes scalability. Trick is that all nodes in the system have to agree on what nodes are in the system. To solve the above problem, you need to maintain a group communication system. Maintaining a membership group means lot of trouble. First problem that that they do not scale very well. Second problem is that when a node has failed, other nodes will detect that and remove the node from the group. When a node is presumed dead, other node reshuffle the data.Most our servers are stateless ( that is they keep their state in a data base). ( there are several ways to do this, and they usually involve heartbeat and a consensus algorithm). The presumed failed node does not know it has failed and continue to work. When it joins back, system need to reshuffle the data again.Two notable exceptions are our CEP server and message broker, but let’s ignore them for now. If you are unlucky, then you can run into the situation where nodes keep coming and going where the system will continue to repair itself.That is network partition the nodes to two clusters.Then system has to make sure only one half is working ( otherwise, you might end up with conflicting updates and stale data).

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