Does Apple store data in more than one location?

As Gail said - you definitely need a backup copy of your Photos Library, if you are using iCloud. It is not an archival backup.

Apple is storing your photos in iCloud, and probably doing everything to keep them safe for you.

1. But Apple does not offer to give you access to the editing history. iCloud Photo library is syncing all changes immediately across all devices. If you delete a photo from iCloud it will be gone everywhere and you cannot recover it without a backup.
2. And Apple is not storing an exact copy of all library items in iCloud, essentially it is storing the moments, albums, photos, some metadata. Your projects and smart albums, and the Faces albums are missing.

From the Photos Help: https://help.apple.com/photos/mac/1.0/?lang=en#/phtf5e48489c

Note: iCloud Photo Library keeps your photos and videos up to date but doesn’t store your projects or Smart Albums. To keep a backup of these items, make sure you back up your Photos library to another storage device.

What iCloud Photo Library is giving you is great, but it does not suffice as a backup. With iCloud you have an off-site storage of your photos. If your house burns down, you can recover your photos from iCloud. But if you delete photos from your library and regret it later, you cannot recover them from iCloud.

And another thing: If you need to restore a complete photo library with many thousands of photos you may not want to have to wait for them to download from iCloud. That can take weeks for a large library. Restoring from a local backup will be much quicker and does not require a stable internet connection.

I can't specifically answer your question about data redundancy on Apple data servers, but I can tell you that using iCloud to archive your photos is not a good idea. iCloud is not an archival service, it is a sharing service. Your photos are all sourced from iCloud, but any action you take on them from any device or computer that is using that iCloud photo library is basically an action that is executed against that library. Lots of people will delete photos from their phone without realizing that doing so will delete them from the iCloud Photo Library.

So you might want to go back to your original habit of creating a safe storage place for your photos, like on your computer's hard drive, or even a standalone drive. You also can look into an Archival Cloud service like Dropbox or SugarSync.

Best of luck,

GB

If I can add this...

Don't worry about Apple being able to produce a copy of your iCloud data in the event "they" have a disaster. I would absolutely count on them to have as much redundancy as is needed to protect "their" copy of your data.

If you read through the discussions here on this topic, you'll find user's cause themselves more data loss than Apple does.

Having said that, putting all your valuable content in *any* one vendor's hands may not be wise. You do not have an agreement with Apple that your data is safe from and and all harm while in their possession. Choose an online storage solution with this in mind.