If Photos library is optimsied on Mac, what does TM backup?

[MrMister111]

I'm trying to decide as I've ran out of space on my internal HDD only iMac wether to use optimised for the photo library or copy it to an external HDD and full resolution.

If I did optimised what does TM backup? I also use iCloud photos library.

Which is best? full resolution on an external HDD for Photos library, or optimised on the internal HDD?

 

[Mikael H]

Having it "optimized" means the canonical copy of your photos are entirely in Apple's control, and if they muck up seriously you could lose all full-res copies of them.

For an iMac that you don't move around a lot, I'd say store the full Photos library on an external drive that you also keep TimeMachine backups of, to yet another external drive.
Combine this with off-site backups, either manual (which one always tends to forget) or automated via something like Backblaze, for data security in case your house would burn down or the computer get stolen.

 

[MrMister111]

Optimised wouldn't work for my offsite cloud backup service, so I've decided to go with an external USB and then add this to my backup service.

Also I'm of the thinking that iCloud photo library is a backup as such. Would take something bad to happen for Apple to lose all my photos surely?

I'm also doing a time machine local backup, I presume that TM will backup my internal, and now external drive that has photos library on?

Rather than have too many drives, I've got a 4Tb and partitioned it for TM and photos library. I know if this drive goes south I lose TM backups and photo library, but then I've still got iCloud library and my other cloud backup service.

 

[Mikael H]

Optimised wouldn't work for my offsite cloud backup service, so I've decided to go with an external USB and then add this to my backup service.

Also I'm of the thinking that iCloud photo library is a backup as such. Would take something bad to happen for Apple to lose all my photos surely?

I'm also doing a time machine local backup, I presume that TM will backup my internal, and now external drive that has photos library on?

Rather than have too many drives, I've got a 4Tb and partitioned it for TM and photos library. I know if this drive goes south I lose TM backups and photo library, but then I've still got iCloud library and my other cloud backup service.

You'll have to decide on a level of paranoia for yourself; I'm just spitting potential risks here, to take into account.

You are right in that iCloud photo library is a secondary copy of your images, but I would never count something that replicates both ways as a backup. I do agree that something seriously bad must happen for that library to disappear, though - but remember that Cloud really only means "somebody else's computer": It's not unheard of for mistakes to happen anywhere humans are involved.