Pega passivation

1.  Passivation allows a requestor, service, or clipboard page to be saved into the Pega Platform database and reactivated later, helping to free up JVM memory and making more memory available to other requestors.
2. When a page is passivated, other pages for that requestor remain in memory, and requestor processing continues normally until that page is needed (such as for read access or for update) and is reactivated into memory. When an entire thread is inactive, the thread context is passivated (including the associated clipboard pages). If the requestor remains idle, eventually the entire requestor context is passivated.When a requestor is activated, the pages that had previously been passivated remain in storage until they need to be activated.
3. The initialization/PersistRequestor prconfig setting or dynamic system setting controls whether time-out passivation occurs. If the setting is not defined or equals OnTimeout, time-out passivation occurs. Time-out passivation is required for high availability environments. To prevent time-out passivation, set this to Never.
4. Passivation occurs through three distinct mechanisms:
1. Page passivation 
1. Used for individual pages, threads, or entire requestors. Page passivation is used to improve system performance by removing pages from the clipboard that have not been accessed by a requestor for a specified period of time. Other pages for that requestor remain in memory, and requestor processing continues normally until that page is needed (such as for read access or for update) and is reactivated into memory. By default, passivation occurs for:
1. Pages that are idle for at least 15 minutes
2. Threads that are idle for at least 30 minutes
3. Requestors that are idle for at least 60 minutes
2. You can configure the time-out periods with the prconfig.xml or dynamic system settings timeout/page, timeout/thread, and timeout/browser. These settings signify numbers of seconds.
2. Timeout passivation – Used for entire requestors. Timeout passivation in a single-node system allows users to resume work without loss of context after a specific period of no activity, with the possibility that they will have to reauthenticate.To enable timeout passivation, use the following prconfig.xml setting or Dynamic System Setting:<env name="Initialization/PersistRequestor" value="OnTimeout"/>
3. HTTP session passivation – Used to free JVM memory and support failover. HTTP session passivation helps to provide high availability in a multinode environment by allowing a cluster to operate in a resilient manner, reducing the risk of loss of data if a node fails.When the Pega Platform is running in high availability mode, the Initialization/PersistRequestor prconfig.xml setting or Dynamic System Setting should be set to "OnTimeout".
5. Passivation storagePega Platform provides two passivation storage mechanisms: database and filesystem. The default passivation storage is database, which is most efficient and robust. You can override the default storage mechanism by setting the prconfig setting "inititlization/persistrequestor/storage" to either "database", "filesystem", or "custom".With database storage, the passivation daemon saves requestor information as an instance of the System-Requestor-Context class, corresponding to the pr_sys_context database table. The daemon saves page details as an instance of the System-SavedPages class in the pr_page_store database table.