The Epoxy Layer
Epoxy (ExIPC) is a shared memory mechanism that enables the Internet Information Services (inetinfo.exe) and the Microsoft Exchange Information Store (store.exe) processes to quickly shuttle data back and forth. This allows for bi-directional inter-process communication between inetinfo.exe (which accepts requests for internet protocols such as WebDav, IMAP4, NNTP, POP3, and SMTP) and the store.exe process. This memory is also used by DSAccess, the Exchange component that caches the Active Directory Information. The Epoxy layer reports statistics pertaining to Epoxy.
If there are performance issues in either the Store.exe or Inetinfo.exe processes, it is common for a queue to build up in the Epoxy as one process performs faster than the other. The Store_out_queue contains messages sent from the Store.exe process to the Inetinfo.exe process. The Client_out_queue contains messages from the Inetinfo.exe process to the Store.exe process. By monitoring these queues, an exchange administrator can determine which queues are building up and degrading performance.
Figure 2 : Tests mapping to the Epoxy layer