Memory Guard continuously monitors and ensures the availability of cluster nodes by preventing the nodes from being evicted when the nodes are stressed due to lack of memory.

• Overview of Memory Guard
  Memory Guard automatically monitors cluster nodes to prevent node stress caused by the lack of memory.
• Memory Guard Architecture
  Memory Guard is implemented as a daemon running as an MBean in a J2EE container managed by Cluster Ready Services (CRS).
• Enabling Memory Guard in Oracle Real Application Clusters (Oracle RAC) Environment
  Memory Guard is automatically enabled when you install Oracle Grid Infrastructure for an Oracle Real Application Clusters (Oracle RAC) or an Oracle RAC One Node database.
• Use of Memory Guard in Oracle Real Application Clusters (Oracle RAC) Deployment
  Memory Guard autonomously detects and monitors Oracle Real Application Clusters (Oracle RAC) or Oracle RAC One Node databases when they are open.