Storage device and method with flexible power loss protection

A storage device comprising:

• a multi-function controller configured to control a plurality of functions requested from a host, wherein the plurality of functions comprises a physical function supporting one or more dependent virtual functions;
• a power loss protection (PLP) capacitor configured to supply auxiliary power to the storage device;
• and
• a PLP controller configured to
• periodically monitor a status of the PLP capacitor, and
• manage a performance list including pieces of performance information supportable for the plurality of functions according to the status of the PLP capacitor, wherein managing the performance list comprises updating the pieces of performance information supportable for the plurality of functions according to a change in the status of the PLP capacitor,
• wherein the PLP controller is further configured to
• provide the performance list to the host in response to a first command received from the host, and
• set a performance level for at least one function from among the plurality of functions by adjusting internal resources of the storage device, in response to a second command received from the host, wherein the internal resources comprise at least one of a PLP data size, or a flush cycle in which write data is flushed from a buffer memory to a nonvolatile memory.