What's the difference beetwen "appendfsync everysec" and VM?

What's the differenc开发者_运维问答e beetwen "appendfsync everysec" and VM ?

The Append Only Filesystem (AOF), writes a transaction log of every command to Redis in an append only log file. This ensures that if the Redis instance crashes, you can recover all the data up to the crash, at the cost of a large log file.

The Virtual Memory (VM) system is a way to increase storage of a Redis system, but potentially swapping unused values to disk. The default (non-VM) operation of Redis is to store everything in RAM, however the VM system allows you to potentially store a bit more data in RAM by swapping values out of RAM - note the keys will always be stored in RAM for fast access.

So, but features are orthogonal - one is a way to persist information, and another is a way to increase memory storage of a Redis system.