AOF stands for Append Only File. The AOF persistence logs every write operation received by the server, that will be played again at server startup, reconstructing the original dataset. By default, the data in a Redis node on ElastiCache resides only in memory and isn't persistent. But there's a dark side to AOF persistence, and that is file size. To disable data persistence, select None. Aof,rdb is a mechanism for two types of redis persistence.