Photo Library Size in GB or/and TB

Photos can handle large libraries. Photos sis supposed to be able to open Aperture Libraries, and an Aperture library could hold up to 1 000 000 photos.

But I second Tony's warning. The size of the library matters for the performance of Photos.

• You will have to be patient, when you need to upgrade the library to a new system version.
• Or when Photos is scanning the library for objects, faces, places, and curating the best photos.
• Or when Photos is updating your smart albums.
• Or when you need to repair the library, because Photos crashed.
• And as Tony pointed out - making backup copies will be very slow as well.

A Photos Library should be on a volume, that has as as much free storage as the size of the library. Repairing and upgrading the library may temporarily need a lot of extra storage. And you may want. to be able to. create a copy of the library as a current backup, before you are doing a major reorganisation of the library. Then you need free storage on the same volume for the copy of the library.

It is very useful, to be able to search all photos without having to switch between libraries, or have all photos you need for a project in the same library, but od you can find subsets of your photos that absolutely need to be together in one library, and other subsets, that never need to be together in one library, create separate libraries, for example, photos for work, and photos for private use.