For all regions, you have options to control memory use, back up your data to disk, and discard stale data from your cache.
You can persist data on disk for backup purposes and overflow it to disk to free up memory without completely removing the data from your cache.
Use eviction to control data region size. Eviction actions are triggered by space-based thresholds.
Use expiration to keep data current and to reduce region size by removing stale entries. Expiration actions are triggered by time-based thresholds.
Keep your distributed cache in sync with an outside data source by programming and installing application plug-ins for your region.