Hi Shane,
Create a new enity in your MS CRM organisation called say "xRMCacheEntity" which has 2 attributes key & value. This keeps the cache in one place i.e. the database that all nodes can access. Then create a class xRMCache which has methods for
Add, Remove, Exists, etc which accesses the underlying entity. You can now call these methods from any node and get back consistent results.
If you need very fast read perf. on this I'd recommend adding a dictionary object on the xRMCache class so the first time a value is read or written you update the dictionary & database record & all subsequent reads are from the local dictionary
object. For this you also need a pre-create \ pre-update plug-in on xRMCacheEntity to send a message to all the nodes to invalidate the cache for updates , inserts, deletes on xRMCacheEntity.
Two other options I'd look at are below.
(a) Use a distribute caching solution, the main ones here for are NCache & AppFabric Cache.
(b) Use a single external source to cache the data that all nodes can reach. This would see you developing say a windows service that had an in-memory dictionary object to cache the items with a WCF interface for communications. So just have Add, Remove,
Exists methods exposed. This is one of the options that Microsoft provide out of the box for load balanced ASP.NET servers which you might actually be able to leverage.
Its the StateServer option in this article, http://msdn.microsoft.com/en-us/library/aa479041.aspx
John
