Near calamity - backups Mac OS X

[Dave2002]

I tried to create a bootable backup of a MacBook Air yesterday using Super Duper. It very nearly went very belly up.
The particular machine has only a small amount of SSD memory - 128 Gbytes - but that's fine normally. The file storage on the machine is around 55-60Gbytes, so should have been possible to back off to a memory stick of 64 Gbytes.

Failed!

What went wrong? The "obvious" answer is that the memory stick got full - but actually that wasn't the problem. The way that SuperDuper works is to copy all the files, presumably on the machine, and transfer them to the external stick, and I guess that if there hadn't been a failure it would eventually have deleted all the temporary files. The failure was almost certainly due to the machine itself running out of available storage. Since this failed, the machine was left in a somewhat compromised state, and required some manual intervention to try to fix the resulting problems.

I have since done a similar backup using Carbon Copy Cloner, but using more control over what gets backed up. This is not an option in the unregistered version of Super Duper, but the trial version of CCC allows enough control to restrict the number of files which get copied on to the USB stick, and the final copy is indeed bootable.

I have used both Super Duper and Carbon Copy Cloner before to do full backups, but not on this particular machine. There perhaps wouldn't normally be a problem on machines with more spare space, particularly if failures do not occur.

So this problem has in one fell swoop converted me to thinking that CCC is the one to go for, for serious backups.

[MrGongGong]

So this problem has in one fell swoop converted me to thinking that CCC is the one to go for, for serious backups.

I use it for all my "serious" and "frivolous" backup tasks
Often on a daily basis

[Lordgeous]

Gosh. You do seem to have a lot of Mac problems Dave! Ive used (registered) Super Duper for years with no problems but never tried backing up to a memory stick. If you make 'serious' backups, what's a frivolous one Mr GG?!

[Dave2002]

LordG

Do you use desktops or laptops? I have access to a range of Macs, and currently I have a problem on a machine - not my own - not even one close to me - to try to fix. The particular machine with the problem is an iMac running 10.6.8 - and it's getting hot. It may have to go to the Apple resting place in the sky, but it seems a shame, as apart from the heat it seemed to be running OK not too long ago, though it is old enough to scrap. I was trying to get a bootable system from another machine - one of ours - and although I have since confirmed proof of concept - being able to boot from a USB memory stick, trying to make the USB "bootable drive" on the particular MacBook Air turned out to be very risky, because of the reasons I've already explained. That was a very close shave - a very near disaster - partly because the data loss would not have been physically large, but very critical for a couple of current projects, and would have been difficult to correct precisely without the appropriate information. It hadn't really been necessary to do that operation on the Air machine, so I nearly succeeded in trashing a good machine for the sake of a sick one.

One other very odd thing is the relationship between Yosemite (which is the OS running on the Air) and Time Machine. The TM drive had not been plugged in for weeks, and was not used to recover after the problem - but when I plugged the TM drive into the machine it did do the backup. Not only that, but it filled in the gaps for most days in the last few weeks - which I now recall is a feature of TM when connected to laptops. What I didn't know was how TM would do or use snapshots - but it appears that it must take the opportunity when it has an external TM drive connected to consolidate any snapshots it has taken onto the TM drive. Actually - on reflection - this does not seem to be odd at all - it's perhaps exactly what TM might be designed to do when there are snapshots available to process. I've only ever considered this before when there are snapshots on the machines and there has not been a recent connection to a hard drive. I just didn't expect it to do that.

AFAIK this isn't a feature of TM if run on desktop machines - only laptops.

https://support.apple.com/en-gb/HT204015

https://www.howtogeek.com/212207/how-to-free-up-space-used-by-time-machines-local-backups-on-your-mac/

It is also possible that the snapshots themselves were part of the problem, preventing Super Duper from working "properly" - but on balance, since it seems that the data was recovered, I'd rather have had SD fail than TM - which might have made the data totally unrecoverable.

It does seem a shame that the snapshot feature is not (yet? AFAIK) a feature of TM running on desktop machines.