cache_low_watermark
                                                    Maximum size of the cache after removing expired entries.
| 
                                                                     Value  | 
                                                                
                                                                     Integer: 0–INT_MAX.  | 
                                                            
| 
                                                                     Default  | 
                                                                
                                                                     400 (MB)  | 
                                                            
| 
                                                                     How to set  | 
                                                                
                                                                     
                                                                          | 
                                                            
| 
                                                                     Usage  | 
                                                                
                                                                     Seldom used.  | 
                                                            
When the maximum cache size is reached, Vocalizer clears expired entries until it gets to this low-watermark threshold.