Add data structure metadata notice to Persistence overview. (#1046)

* Add data structure metadata notice to Persistence overview. * Update docs/modules/storage/pages/persistence.adoc Co-authored-by: rebekah-lawrence <[email protected]> * Update docs/modules/storage/pages/persistence.adoc Co-authored-by: rebekah-lawrence <[email protected]> * Update docs/modules/storage/pages/persistence.adoc Co-authored-by: rebekah-lawrence <[email protected]> * Update docs/modules/storage/pages/persistence.adoc Co-authored-by: rebekah-lawrence <[email protected]> * Update docs/modules/storage/pages/persistence.adoc Co-authored-by: rebekah-lawrence <[email protected]> --------- Co-authored-by: rebekah-lawrence <[email protected]>
hazelcast · Mar 8, 2024 · 302533b · 302533b
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diff --git a/docs/modules/data-structures/pages/managing-map-memory.adoc b/docs/modules/data-structures/pages/managing-map-memory.adoc
@@ -16,7 +16,7 @@ IMPORTANT: Expiration and eviction policies do not apply to locked map entries.
 
 An expiration policy limits the lifetime of an entry stored inside a map. When an entry expires it can no longer be read from the map and is scheduled to be removed to release memory. The actual removal will occur during the next garbage collection cycle. 
 
-To configure an expiration policy, use the elements `time-to-live-seconds`and `max-idle-seconds`.
+To configure an expiration policy, use the elements `time-to-live-seconds` and `max-idle-seconds`.
 
 === time-to-live-seconds
 
@@ -25,7 +25,7 @@ This element is relative to the time of a map's last write. For example a time t
 - Default value: 0 (disabled)
 - Accepted values: Integers between 0 and `Integer.MAX VALUE`.
 
- By default, this configuration element applies to all entries in a map. To configure TTL for specific entries, see  <<evicting-specific-entries, Setting an Expiration Policy for Specific Entries>>.
+By default, this configuration element applies to all entries in a map. To configure TTL for specific entries, see  <<evicting-specific-entries, Setting an Expiration Policy for Specific Entries>>.
 
 === max-idle-seconds
 

diff --git a/docs/modules/storage/pages/persistence.adoc b/docs/modules/storage/pages/persistence.adoc
@@ -22,6 +22,18 @@ Clusters can use persisted data to recover from the following scenarios:
 You can persist the following:
 
 * Contents of map or JCache data structure
++
+[IMPORTANT]
+====
+Hazelcast does not persist the metadata of your data structure entries, including time-to-live (TTL), to disk when xref:storage:configuring-persistence.adoc#quickstart-configuration[Persistence is enabled].
+
+For example, assuming the following:
+
+* The cluster was started with persistence enabled and TTL configured to three hours for your map entries.
+* The cluster was shut down and restarted two hours after the initial cluster start up.
+
+As TTL is metadata, which is not persisted when the cluster restarts, it is reset to the configured three hours from the time of the restart. Two hours have already passed before the restart, so the map entries now have a TTL value of five hours.
+====
 * Streaming job snapshots
 * SQL metadata, to avoid loss of SQL mappings, data connections, or views after a cluster restart.