Apple photos/iphoto library move to external

[hasole]

I have an iMac that had its iPhoto library upgraded to photos many moons ago.

I now need to move it to an external drive due to the size of it.

In theory the photos library references the masters out of the iPhoto library. Does that mean I should copy both libraries to the external drive?

Or if I only copy the photos library, will it copy the masters that it had referenced from the iPhoto library?

 

[ApfelKuchen]

I think your safest strategy is to either move both libraries to the external, or delete the iPhoto library and then move the Photos library.

I'm not sure how hard linking works in this case - whether a hard link persists when a library is moved to another drive (leaving whatever files that had been part of the original iPhoto library on the internal drive), or whether a physical copy of each hard-linked file is made when the library is moved off-disk.

You call it "referencing," but it's not like a simple, "here's the actual location" link as you'd find with referenced images. The file system associates the file to both libraries, as if it's physically present in both. That's why both libraries have a similar size right after a conversion, even though the master images haven't been duplicated.

 

[Dave Braine]

If Photos has imported your photos from iPhoto, then you can safely delete your old iPhoto Library.

 

[hasole]

I've copied both libraries to an external drive and it wrote about 700gb for each library. The iMac has a 1TB hdd in so, so one can only assume it made a standalone copy of the photos library with everything in it.

Now to delete the local copy....