Time Machine vs SuperDuper

TidBITS Talk
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I’ve been a loyal user of Superduper over the years. It’s been incredibly reliable and has saved me several times. However, I’m thinking it might be a better solution for my wife, who unlike me, does not obsessively back up every day… or week… or month. You get the picture. TM seems to be more automatic – leave the drive plugged in all the time and the backups happen in the background.

Thoughts?

I did set it up on my machine just to try it and it seems to work fine. I haven’t tried to restore from it, but that process does seem to be built into the Apple process.

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Both have their place, and IMO, both should be used as a part of a comprehensive backup solution.

Time Machine is a great system for its purpose - making hourly snapshots of a running system, stored on external storage. But when your internal storage fails, you can’t use it for anything other than a source for restoring your system to a new/replacement storage device.

A bootable disk clone, on the other hand, solves that problem. If your internal storage fails, you can boot from this device and keep running (possibly at reduced performance if it’s a slow device like a hard drive) while waiting to receive and install replacement storage (which might be a replacement computer if the storage is soldered to its motherboard).

The downside of a bootable clone, of course, is that it probably isn’t going to be making clones every hour, the way Time Machine does.

But these are not your only options.

Off-site backups (e.g. storing a backup device at another location or a cloud-based backup service) protect you against disaster trashing your location. (e.g. flood, fire, hurricane, etc.), allowing you to buy new equipment at a new location and get back up and running from that backup.

And archival backups (hard drive, tape, etc.) will let you go get old information long after the data has been deleted/changed, in case you ever require access.

All these are parts of a comprehensive backup/data recovery solution. You should investigate all of them, determine the costs (both money and time), evaluate the risks, and use them to evaluate what you need to implement, what would be nice and what is unnecessary.

For myself, I use one Time Machine volume and two bootable clones. I used to also burn copies of my data to DVDs (for archival purposes) before every major OS upgrade, but the size of macOS has gotten so large that this is no longer practical. I might start doing this again in the future with Blu-Ray media, however, since 25 GB per layer may once again make this practical.

Sadly, tape backup, which I really like, has gotten far too expensive for non-enterprise use. Any drive with large enough capacity to back up a system onto one or two tapes (in my case, this would be LTO-6 or later, with 2.5 TB uncompressed capacity per tape) is far too expensive for a home user to ever consider.

Bare LTO-6 drives cost about $1000-1500 and have SAS interfaces. Only one company, mLogic makes a Mac-compatible external drive (with a Thunderbolt interface), and it sells for $3500 (MSRP - I’ve seen it for about $3000 on Amazon). Far too much money to buy one for personal use.

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SuperDuper does have a scheduling feature so that it cans be set to run, say, daily at 3 am, assuming, of course, the computer is on at that time. I still have SD set to make a bootable clone daily on our iMac, which is always on, and the drive is always connected.

For my MacBook Air, I use Carbon Copy Cloner to do the same, as it has a feature to start a cloning process when the computer sees that the drive has been mounted. That works great for me. I do a clone on the MBA maybe once a week or so, and it’s more of a just in case backup for me than anything else.

For my main backups I am using Arq to backup both to a disk connected to an always on Mac Mini locally and also to a couple of online cloud services. It’s basically similar to Time Machine except I am not using a locally mounted disk. That’s what I would use to recover my system in case of failure at this point. I really don’t see much need for a bootable clone anymore (though out of inertia more than anything I still make them.)

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I do both. They each do something a bit different and in that they complement each other well. Recall that you should never rely on only one backup strategy.

Something I always shied away from are versioned/incremental clones. I leave versioning to TM, and when I clone with SD it’s always format disk first, then clone, and then never touch again (except to read of course). But then again, I have many disks I can rotate through so YMMV.

I used to be really big on bootable clones, but these days with built-in recovery partitions I realize it’s not really all that important anymore, and judging by what Apple is doing in the M1 transition, its writing is on the wall anyway.

Offsite is good to have. That said, I’m not at all a fan of cloud backups. They’re usually either expensive or crap and they’re always slow. Fortunately, a set of disks you simply store at another location (eg. work vs. home) does the trick just fine. With lots of disks lying around, you probably want to consider encryption (eg. FileVault or similar).

Edit: @ace just put out an excellent summary on the topic: The Role of Bootable Duplicates in a Modern Backup Strategy - TidBITS

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CCC has a feature called Safety Net, which I understand allows versioning. Turning it off generates a warning like “Files unique to the destination will be deleted.” Does SD have a similar capability that you choose not to use? If files unique to the destination would really be deleted (that is, everything not current would be gone), would you still format the disk first?

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Thanks all – it’s very helpful to see the different strategies. I really appreciate it. I’ll also check out the TidBits article Simon referenced.