There is a being who has been alive for as long as there has been life on earth. It has the ability to anomalously produce matter from its body out of nothing. Through the production of microfine strands of flesh dotted with tiny eyes, it has the ability to see and be cognizant of everything happening on every square micrometer of planet earth, all at once.

It needs a brain large enough to store all of this information, since it wants to remember everything that has ever happened on earth.

Presuming it uses storage space with the same efficiency as a human brain, approximately what volume/size would a brain have to be to remember everything that has ever happened on earth from the dawn of life to present day, and that brain was only used for storing memories? Would it be planetary or celestial in size, or relatively small enough to be kept on earth?