Broker Server requires a substantial amount of memory to hold the documents that clients publish. Most of the memory is used to hold volatile documents, which exist only in memory. However, a certain portion of memory is used to cache guaranteed documents and other objects that are kept in queue storage.

To perform optimally, Broker Server needs enough physical memory to simultaneously hold:

If the operating system begins paging documents to virtual memory, the performance of the Broker Server drops significantly. Extreme out-of-memory conditions can cause the Broker Server to exit and restart.