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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 >=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?

stevec
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    Also note that iCloud doesn't protect from accidental deletion, something I have been known to do from (ahem...) time to time... – Steve Chambers Jul 25 '20 at 14:03
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    @SteveChambers yep, this is why people say a syncing service is not a backup. – At0micMutex Jul 25 '20 at 22:45
  • Does this answer your question? Does Apple make backups of iCloud? – Jörg W Mittag Jul 26 '20 at 06:56
  • @JörgWMittag very interesting. It seems more about when a user accidentally deletes something . But it touches on best practice e.g. "Does Apple make backups of iCloud? From an infrastructure management perspective, yes they do.". But the second answer says "Not sure whether it's officially known if Apple does or doesn't make backups". I guess my question is asking is this enough? (i.e. to trust a single cloud). I felt like if they make multiple copies then it would be, but the answers below point out that it may not be. Very interesting reading – stevec Jul 26 '20 at 07:21
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    It never hurts to have an extra copy of your important data. – iBug Jul 26 '20 at 07:34
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    @stevec: The main point is that for the purposes of backups, it is irrelevant. If you want to "back up" files, then it is irrelevant whether iCloud has backups or not, because iCloud is a synchronization service, not a backup service, and thus cannot be used for backups anyway. (Not directly, at least. You can, of course, use a backup tool, and then store the output of that tool on iCloud.) – Jörg W Mittag Jul 26 '20 at 08:10
  • @JörgWMittag intersting. I always thought it (iCloud) was a substitute for the old “external hard drive” way of doing things? Right now I back up using an external hard disk (only one), so I was thinking of ditching that approach in favour of iCloud, and wasn’t sure if it should be just iCloud or iCloud + some other storage. – stevec Jul 26 '20 at 08:58
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    @stevec: iCloud is a sync service. It syncs everything you are doing. If you accidentally delete all your files, iCloud will do its best to also delete all your files on iCloud, on your other Mac, on your iPad, and on your iPhone. That's the whole point of a sync service: to make sure the state is the same on all devices. – Jörg W Mittag Jul 26 '20 at 09:01
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    There is another fundamental assumption in this question that I like to call out, which is that the only thing you have to worry about is whether Apple will accidentally lose your data. However, there is lots of precedent for cloud storage providers intentionally removing your data (or at least your access to it). For example, if you were to enter the iPhone app business, and Apple decided your app violated policies; or if your account became associated with a reported-stolen credit card; or if Apple mistakenly believed one of these things -- you might find your Apple account to be no more. – Glenn Willen Jul 26 '20 at 10:25
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    "The cloud is just someone else's computer". – Eric Duminil Jul 26 '20 at 15:41
  • @Glenn that’s why you don’t poop where you eat. Multiple (e.g. Apple) accounts, one for your valued stuff (cloud data, media purchases) and the other for your forum activities, app sales etc. Not least, you want to avoid commingling any business venture with your personal account, so it can be separated later for liability, tax and ownership-split reasons. – Harper - Reinstate Monica Jul 27 '20 at 16:29
  • Syncing is not backup, but if you run rsync without the delete option first, and then run the subsequent deletion with a dry run and check what all it thinks should be deleted you are a lot closer. – Michael Jul 27 '20 at 20:32
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    I remember an incident when iCloud was initially introduced and promoted with "All your documents. On all your devices." After some sort of glitch on Apple's side, I lost all my documents in Pages at once. On all my devices. (Support suggested to restore the files from my backups, by the way.) – Dmitri Urbanowicz Jul 28 '20 at 11:47

4 Answers4

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The new paradigm is…

"Any data which is stored in fewer than three distinct locations ought to be considered temporary."

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'.

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

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

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

  2. Backblaze [other offsite backup structures are available] which has copies of everything in 1, 2, & 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 & 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 & nearly 20 years of unbroken historical data.

Tetsujin
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    This is a very common setup - very excellent choices in vendors. Do you recommend anything for your boot drive cloning or is Disk Utility / asr / scripts enough for you? – bmike Jul 25 '20 at 13:50
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    I've always used Carbon Copy Cloner - just because it was the first one I discovered many years ago & has never let me down yet. I don't script it, I just do a manual clone of 'since last time' whenever I remember. If I did have a failure, anything missing would be on Time Machine &/or Backblaze, so I don't worry too much, it's just a fast 'get out of jail free' card for a single drive catastrophe. – Tetsujin Jul 25 '20 at 13:51
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    This is precisely what we use it for - speed to recovery - not the primary source. We’re about 50/50 on SD / CCC - neither has really disappointed us ever so whichever starts, sticks for us as well. – bmike Jul 25 '20 at 14:32
  • I store important files* (not full Mac backups) in iCloud, Dropbox, Google Drive, and rotating TimeMachine backup disks both at home & at the office for full macOS restores. I figure that if BOTH TimeMachine back drives get destroyed in the same event, (they're separated by about 10 miles,) I have far more problems to worry about than recovering my data.:-) *irreplaceable scanned documents like wills, leases, birth certificates, tax records, etc.) – IconDaemon Jul 26 '20 at 01:42
  • +1 for Carbon Copy Cloner. It works great, and it's really easy to check if the backup has be done correctly : simply try to boot from it. I've seen Time Machine fail spectacularly twice. A few files were corrupt, and all I had left was the shiny interface, one "Restore" button which didn't work and bazillions of non-standard folder hard links. – Eric Duminil Jul 26 '20 at 15:47
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    @EricDuminil - I've had many Time Machine fails. It seems to be fine for rescuing the odd file or two, but for restore or migration, nada. See https://apple.stackexchange.com/questions/392734/migration-assistant-fail which I've still not solved. – Tetsujin Jul 26 '20 at 17:46
  • @Tetsujin: TimeMachine is worse than no backup IMHO, because it gives a false sense of security. There are many examples of fine design by Apple, TimeMachine isn't one of them. Please consider not advertising TM in your answers. – Eric Duminil Jul 26 '20 at 21:16
  • "iCloud is not primarily a backup solution, it is a sync solution". Does iCloud really not save snapshots of data and allow to restore older versions? Even for a sync service that's awful. – Voo Jul 27 '20 at 15:11
  • It is what it is. Personally I don't use it, except to keep my keychain synchronised. It also automatically backs up my phone, but I've never used that either. – Tetsujin Jul 27 '20 at 15:13
  • "By default, Backblaze saves any old versions or deleted files for 30 days." (source). Adding this as this was not mentioned earlier. – Alexander K. Sep 14 '20 at 00:31
  • …with the option of "you can extend that version history to 1-Year or Forever for an additional fee" – Tetsujin Sep 14 '20 at 06:15
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iCloud is not a backup. It is a synchronization service.

There is a fundamental difference between the two. When you accidentally delete a file, then

  • a backup makes sure that you can restore the file again, whereas
  • a synchronization service makes sure that you can never again restore the file because it synchronizes the deletion event everwhere.

As you can see, this makes the synchronization service in some sense the exact opposite of a backup.

The same applies to RAID, by the way.

Jörg W Mittag
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  • “synchronization service...exact opposite of a backup” is an interesting way to look at it. I personally find both of these extremes stupid – pure backups cause an inscrutable mess of mismatching versions, and also often end up using vast unnecessary space for really obsolete files, whereas pure sync causes an inscrutable loss of overview which version I'm at. Proper VCS software handles both sync and backup concerns; I use Git for everything, with Git Annex for big files so I can easily see which file is where and decide if that's secure enough. – leftaroundabout Jul 26 '20 at 13:26
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    @leftaroundabout If your backup strategy results in a mess of mismatching versions you don't really have one :-) And I'm not sure how git can be the universal solution here, I don't see it working for full system backups, databases etc, it also doesn't automatically provide multi-device backups (as in having one working system and three independent backup stores). – nohillside Jul 26 '20 at 19:02
  • @nohillside well, it doesn't result in a mess, precisely because my backup strategy is to let git handle all of it! And yes, with git-annex this provides excellent support for multi-device backups. –Full-system backups and databases are another story, yes, but the former is arguably obsolete (use proper containerisation, setup scripts, robust package managers such as NixOS etc.) whereas a decent database will presumably have dedicated backup mechanisms built-in, no? – leftaroundabout Jul 26 '20 at 20:45
  • @leftaroundabout I'm looking into git-annex right now which I didn't know before, so thanks for the link. Not sure it works as a solution for the common user though, or in the context of the question on top :-) – nohillside Jul 27 '20 at 06:19
  • Remember - RAID is not a backup – MetricSystemAdvocate Jul 30 '20 at 09:24
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Yes. I have one mac that I set to download originals - no optimizing space. This way I have a guaranteed local copy of my Music (formerly iTunes) Library and content, my Photos (formerly iPhoto) Library and content and all containers and app-data and files stored in iCloud.

I back these up to Time Machine. I have two drives that Time Machine backs up to - one that’s connected for 3 months and another that’s off-site. Each quarter, I disconnect the drive that’s online and swap it out with the off-site one that comes back and stays connected for the new quarter.

I limit my lossage to the new files only should I lose both iCloud and my home to a fire or accident.

I know some other people use SuperDuper or Carbon Copy Cloner or Arq but I haven’t needed these excellent tools for personal use (I use each of the above professionally and can vouch for how well engineered they are - spend money with one of them if you don’t trust Time Machine).

Here are my truths:

  • iCloud is not a backup I trust for irreplaceable items like photos, legal documents, important files.
  • RAID is not a backup for anything
  • I’m more likely to mess up than Apple is. I am primarily protecting me against myself losing control of my account or messing up.
  • I gladly outsource backup tools to the professionals (just like I outsource music syncing and photo syncing to Apple).

Every time the bill comes due, I have a drink and appreciate I’m not spending hours fixing my hacked together scripts to back up or sync. I’m then refreshed to earn more than enough money to pay someone to manage these tasks for me. The time I save is way more valuable than the cost of one time backup service or $13 a month to Apple for iCloud storage and music service.

bmike
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While I don't want to labor the points already made, I do believe it should be called out that "accidental deletion" is not the only failure mode that can ruin your iCloud "backup" (i.e., sync). Other possible failures, due to iCloud sync'ing and not maintaining a fully "independent" (i.e., non-local), "distinct" (i.e., non-synchronized), "time-dated" (i.e., snapshot) copy of your data are:

  1. Ransomware will ruin your day: the iCloud "copy" will be encrypted along with your (local) data. Note that this can also be ruin a snapshot service if there is insufficient excess capacity to hold at least 2x the capacity of your data. Without sufficient excess capacity, encrypted data will overwrite old snapshots (indeed possibly all your snapshots).

  2. Multiple device synchronization can be a foul up: iCloud can and does have issues if a device has been offline for an extended period of time and is then re-introduced to synchronization. It can and does attempt to "add" the old data to the latest data. I've seen it, it isn't pretty.

Note: iCloud could be significantly improved if it would provide synchronization of a Time Machine backup-- especially if the Time Machine backup were made to separate, write-once ("WORM") media.

newyork10023
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