Need guidance on adding Time Machine to my clone-based backup strategy.

I have an early-2015 MBP with a 1 TB internal SSD. Using Carbon Copy Cloner, my backup strategy has been to clone nightly to a desktop external HD, and then ~once/month swap out a portable HD clone I keep in a bank safe deposit box (so I'm combining local and remote backups).

I'm thinking of adding Time Machine to this, to help me recover a file I might have deleted and want back. What's the best way to do this? Should I add a Time Machine partition to both my internal drive and my desktop backup and have Time Machine back up to both? Or should I just have Time Machine back up to the external, which would allow me to backup a much larger Time Machine folder (I could upgrade to a 2 TB or 3 TB external desktop drive for ~$100)?

And should I also add a Time Machine partition to my portable drives so I can manually copy my Time Machine backup files to them, or is manually copying the Time Machine files problematic? It looks like it's more involved than just dragging the backups.backupdb folder over to the portable drive (https://support.apple.com/en-us/HT202380), but maybe dragging the folder is all you need to do until such time as you actually want to access Time Machine from the remote drive.

Thanks!

Welcome

A few points of general principle which may assist.

Firstly, use a separate and dedicated EHD for Time Machine (TM). Do not partition an existing EHD and add TM to some other backup (BU) on that EHD. Reason: disk fails (all do eventually) and you lose everything. And do not partition your Mac HD for TM for the same reason.

Next: as a general rule, the storage capacity of the EHD running TM should be 1.5 to 2 times that of your Mac's HD.

TM is designed to run on its own; not to be tinkered with manually. It automatically does a BU hourly for 24 hours, daily for the next month and so on. Great, as you say, for recovering accidentally deleted files. TM is not bootable, but can be used to restore your entire system including settings to a new Mac (in the future) or to a new Int HD should that have to be replaced.

You already have an excellent BU strategy using CCC with local and off-site BUs. And CCC is bootable.

TM will sit very comfortably with this strategy.

If you need step-by-step guidance on setting up TM, just ask; but it seems to me that you are already well clued up on Mac matters.

Ian

Thanks Ian!

IWT said:

as a general rule, the storage capacity of the EHD running TM should be 1.5 to 2 times that of your Mac's HD.

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Just based on this, it seems I should not put my principal TM on my internal, since it means my SSD would quickly fill up, which I understand is not good for its performance. Though I'll mention my reasoning for putting the TM on my internal was so that, if I were away from home and needed a deleted file, I'd have access to it (without having to use the Cloud).

Come to think of it, what about the idea of having a small TM, with limited history, on an internal (say, just going back a week or so)? That way, if you accidentally delete a file, you can retrieve it directly from your internal.

IWT said:

Do not partition an existing EHD and add TM to some other backup (BU) on that EHD. Reason: disk fails (all do eventually) and you lose everything.

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This I don't understand. Consider two scenarios, both involving two EHDs
1) CCC clone on one EHD, TM on the other (as you suggest)
2) Both EHD's partitioned to have CCC on one partition and TM on the other.

In scenario one, if one EHD fails, you lose either your CCC clone, or your TM backup. In scenario two, if one EHD fails, you retain both your CCC clone and your TM backup. So it seems scenario two provides more robust backup protection. Is there something I'm missing here?

Can TM be configured to backup to two different attached drives?

And, more broadly, if not manually, then how do people backup their TM backups, so that if the drive that has your primary TM fails, you still have a backup for it?

Backing up a backup.. hrm.. just do two separate TM instances and an occasional bootable. Far easier, less complicated, and thus.. less prone to error injection.

Dysfunction said:

Backing up a backup.. hrm.. just do two separate TM instances and an occasional bootable. Far easier, less complicated, and thus.. less prone to error injection.

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So one TM instance would be on my desktop EHD, and the other would be on the portable EHD I store at the bank (actually, I have two portables, for easy swapping, but that doesn't change anything). But the question is: how should I do the second instance, on the one I keep at the bank? When I bring it back from the bank to update it, and run TM, isn't it going to miss all the history that's on the primary instance? That's why I thought it might make more sense to just copy the TM backup folder from the desktop EHD to the portable EHD when I brought it home for updating. And it seems easier to me to just drag and drop a folder than to do a new TM backup (assuming that's all I need to do).

It'll ask if you you wish to replace your old TM drive, or use both. Then, do a full backup regardless.. and start incrementals. It simply wants to know, so it'll keep track of the backups on both correctly.

Dysfunction said:

It'll ask if you you wish to replace your old TM drive, or use both. Then, do a full backup regardless.. and start incrementals. It simply wants to know, so it'll keep track of the backups on both correctly.

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So suppose I have TM on my desktop EHD and it thus has incrementals for the past month (and further back). Now I bring home my portable EHD, which has been sitting at the bank for the past month. You're saying that, if I do a full TM backup on the portable EHD while the desktop EHD is connected, it will synchronize the TM on the former with the latter, so the portable will now also have all the incrementals for the last month?

It might help if I clarified what I'm trying to do, expanding on the what I said in my first post:

I'm not planning to use TM as a backup in case of disc failure; that's what the clones are for. If my disk fails or is corrupted, I find being able to boot to, and/or restore from, an external clone, to be far easier and cleaner than using TM. Instead, I just want to add TM as a form of version control -- to allow me to gain access to files I may have deleted (the clones won't help me with that).

So, for me, the two different TM's aren't a backup and a backup of a backup. Rather, I think of them as a version-control database, and a backup of that database.

chemist said:

So suppose I have TM on my desktop EHD and it thus has incrementals for the past month (and further back). Now I bring home my portable EHD, which has been sitting at the bank for the past month. You're saying that, if I do a full TM backup on the portable EHD while the desktop EHD is connected, it will synchronize the TM on the former with the latter, so the portable will now also have all the incrementals for the last month?

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You can as many TM BUs as you like. In fact on my iMac, there is a built in option of having 2 TM BUs. The OS backs up number 1, then the next hour, backs up to number 2.

So, taking your situation: You have, say, TM 1 attached to your Mac. After a month, off it goes to the bank and you BU to TM 2. After another month, you bring back TM 1 and mount it. It remembers exactly where it was and backs up everything that has changed since the last time. Repeat as often as you wish. In theory, you could have 3 or 4 TMs on the go. Each time you mount one, it brings things bang up to date.

The same is true for your CCC BU. As many as you want. Each time you mount one, it backs up to date.

Whilst I obviously understand your comments about a TM partition on your Mac's HD, this really is a bad move. The whole essence of a BU is that it is physically separate from your Mac (either connected, or remote, as in the bank).

Yes, I take your point of having both a TM and CCC BU on 2 EHDs; but you are making a lot of work for yourself.

There are few as obsessed with back ups as me! But one has to be practical.

EHDs these days are remarkably cheap. So, why not have four. Two for TM (one attached, the other in the bank, alternating each month) and ditto for CCC.

I would not advise any sort of "drop & drag" onto TM or CCC. They are not designed for this operation. Let them undertake their own incremental BUs in their own way.

If you are interested, what I do: is have two TMs, each on a separate EHD and permanently mounted. I have one clone BU on another EHD which I update every 7-10 days (the EHD is unmounted between back ups). Finally, I manually BU my iPhoto, iTunes & Aperture Libraries and my Documents Folder to yet another EHD about once a month. OK, I don't keep anything off site! But I do use iCloud and I do use Dropbox for vital or precious things. (And I do use Evernote, although that's not really a BU).

Ian

IWT said:

You can as many TM BUs as you like. In fact on my iMac, there is a built in option of having 2 TM BUs. The OS backs up number 1, then the next hour, backs up to number 2.Ian

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Good to know, thanks.

IWT said:

So, taking your situation: You have, say, TM 1 attached to your Mac. After a month, off it goes to the bank and you BU to TM 2. After another month, you bring back TM 1 and mount it. It remembers exactly where it was and backs up everything that has changed since the last time. Repeat as often as you wish. In theory, you could have 3 or 4 TMs on the go. Each time you mount one, it brings things bang up to date.
The same is true for your CCC BU. As many as you want. Each time you mount one, it backs up to date.

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I'm afraid your approach won't work -- TM is not the same as CCC. If follow your procedure of alternating, I'll end up with two different TM backups that have snapshot gaps for alternating months. Consider the following: Suppose I have a file I create on May 10 then delete on May 15. That file will be accessible through the current TM backup, which runs continuously on my desktop. Now further suppose that, at the end of May, I do as you suggest, and swap with the alternate drive and perform a TM backup onto it. If I do this, the TM backup on the alternate won't have that file or, indeed, any file that was created and then deleted during that month! I.e., unlike with CCC, neither of the TM versions on the two drives will be compete -- they'll each be missing all the intermediate backups that occurred during the time they were disconnected.

The better way would be to have a primary TM drive running continuously, and then to drag its sparse bundle file to a portable I bring in from the bank once a month. That way I will have two complete TM backups, with no gaps.

IWT said:

I would not advise any sort of "drop & drag" onto TM or CCC. They are not designed for this operation. Let them undertake their own incremental BUs in their own way.

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I spoke to Apple Support, and they said that, with Yosemite, this is OK (for TM).

IWT said:

Whilst I obviously understand your comments about a TM partition on your Mac's HD, this really is a bad move. The whole essence of a BU is that it is physically separate from your Mac (either connected, or remote, as in the bank).

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Sorry, this doesn't make sense to me. Note that I was specifically talking about having a small TM backup on my internal in addition to the two TM backups externally, vs. only having the two TM backups externally. Clearly, the former is not less secure than the latter!

Again, the reason for this would be to have access to some snapshots when I'm away from home and thus don't have my EHD's with me.

IWT said:

Yes, I take your point of having both a TM and CCC BU on 2 EHDs; but you are making a lot of work for yourself. ... why not have four. Two for TM (one attached, the other in the bank, alternating each month) and ditto for CCC.

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Sorry, this also doesn't make sense to me. It seems easier to manage two physical drives (with a TM and CCC partition on each) than to manage four physical drives.

IWT said:

OK, I don't keep anything off site! But I do use iCloud and I do use Dropbox for vital or precious things. (And I do use Evernote, although that's not really a BU).

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I'd highly recommend a full clone in a safety deposit box! If there's a fire or theft at your house and your equipment is all lost or destroyed, this would ensure you've got an entire bootable disk available to you.

I said before; you are a very clued up person. It's personal choice after all and opinions are just that. So, go with your flow and do what seems natural to you. And good fortune to you. It's been an interesting discussion and I've enjoyed the exchanges.

Ian

IWT said:

I said before; you are a very clued up person. It's personal choice after all and opinions are just that. So, go with your flow and do what seems natural to you. And good fortune to you. It's been an interesting discussion and I've enjoyed the exchanges.

Ian

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Likewise Ian. This discussion was very helpful to me -- it helped me go through the options and clarify my thinking.