[CN-1246]: Add note for map and cache persistence to persistence page (…

…#218)

Co-authored-by: rebekah-lawrence <142301480+rebekah-lawrence@users.noreply.github.com>

docs/modules/ROOT/pages/backup-restore.adoc

@@ -31,6 +31,8 @@ uses the latest agent version that is compatible with its version.
 
 NOTE: Make sure to calculate the total disk space that you will use. The total used disk space may be larger than the size of in-memory data, depending on how many <<local-backup, backups>> you take.
 
+IMPORTANT: If you want to enable persistence for a map or cache you must enable it in the Map or Cache CRs by setting `persistenceEnabled: true`. For more information, see xref:map-configuration.adoc#configuring-the-map-resource[Configuring Map] and xref:cache-configuration.adoc#configuring-a-cache-resource[Configuring Cache].
+
 [[trigger-backup]]
 == Triggering Local Backups