Question about Synology RS1221+

The power supply units of the RS1221RP+ are also hot-swappable, i.e. they can be replaced during operation. This means that in the event of a defective power supply unit, the second one takes over and the first one can be replaced without stopping the NAS.

The only difference is the RP, which stands for redundant power supply. The model with RP therefore has a second power socket. This is made for the case of a power failure, the second socket must of course have power available ;)