Should important files in iCloud also be backed up elsewhere? It is commonly accepted that any files stored on a personal external hard drive should also be backed up elsewhere (in at least one other drive/location) since external drives can and do fail and having &gt;=2 copies greatly reduces the chances of important data being lost.
Is the same measure necessary for important files stored in iCloud?
Knowing that any large company's 'cloud' storage would likely be much better and safer than someone's personal external hard drive helps, but are they still susceptible to failure? Do files get backed up within iCloud, that is, are there multiple copies of the files in iCloud in case any one of Apple's datacenters gets destroyed?
The basic question I am trying to answer is: is storing important files in iCloud enough, or should the extra precaution of storing important files elsewhere (e.g. google drive, an external hard disk, etc) also be taken?
The new paradigm is…
&quot;Any data which is stored in fewer than three distinct locations ought to be considered temporary.&quot;
Late Edit:
Don't use a sync solution as a backup.
iCloud is not primarily a backup solution, it is a sync solution. It will come back to bite you hard if you accidentally delete a file from one device… the helpful sync service will then dutifully delete it from every device.
For 'distinct locations', personally, I use 4, in degrees of 'distance'.

My Mac, which has not only my Mac data but also my iDevice backups.
Time Machine, containing all of 1.

1 &amp; 2 are both in the same building, so if the house burns down, I need another location, off-site.

iCloud, containing only a subset of 1 &amp; 2 [primarily iPhone backups, just because they happen automatically] which is not enough to recover everything in case of disaster.

Backblaze [other offsite backup structures are available] which has copies of everything in 1, 2, &amp; 3 above.


I also have my boot drive cloned, for rapid recovery in case of drive failure, but that is also in the house, so classes as part of 1 &amp; 2.
I consider iCloud to contain my keychain in case of catastrophe. I don't consider it as any kind of 'storage', per se. I don't trust it with my photos or my music, for instance, I have all that data stored in 1, the Mac. I consider my Mac to be the primary location for all my data. It has 13TB of storage &amp; nearly 20 years of unbroken historical data.