Cache data on Multiple Hosts in AppFabric

Question

Let me first explain that I am very new when it comes to use AppFabric for improving the Responsiveness of your application. I am trying to configure the Server Cluster with 2 Nodes over XML provider over Network Shared location.

My requirement is that the cached data should be created on both the Hosts so that If One of the host is down my other host in the Cluster should be able to serve the request and provide the cached data. As I said I have 2 Host in my Cluster and one of them is defined as Lead Host. Now when I am saving the data in cache I could not see the data in both the hosts (Not sure is there any specific command where you can see the data in a specific host). So what I want to test is that I’ll stop one of the Cache host and try to see if still I able to get the data from the second cache host.

thanks in advance -Nitin

Answer 1

What you're talking about here is High Availability. To enable this, you'll need to be running Windows Server Enterprise Edition - if you're on Standard Edition then you just can't do it. You also really need a minimum of three hosts, so that if one goes down there are still two copies of your cached data to provide failover. If you can meet these requirements then the only extra step to create a highly-available cache is to set the Secondaries flag when you call new-cache e.g.

new-cache myHACache -Secondaries 1

There's no programmatic way to query what data is held on a specific host, because you only ever address the logical cache, not an individual physical host.

Answer 2

From our experience, using SQL authentication to the database does not work. Its clearly stated that only Integrated Security option is supported. Also we faced issues with the service running with "Integrated Security" since our SQL cluster was running under a domain account and AppFabric needs to run under "Network service" and we couldnt successfully connect to the sql cluster from AppFabric service.

This was a painful experience for us and I hope AppFabric caching improves the way it sends out "error messages and error codes". And also allows us to decide how we want to connect to the sql. KInd of stupid having to undergo this pain of "has to run as Network Service" and "no SQL authentication".