Problem copying time machine backup
 

I'm trying to copy my time machine backup from an old external drive to a new one.

The old drive has some kind of low level file system corruption that fsck can't fix which means it can only be mounted read only. Apart from being read only everything else seems fine. All the data is there and readable. I've tried doing a block level copy using disk utility but that's not working because it also copies the corruption. File level copies work but break when they hit time machine's folder hard links. That's what lead me to SuperDuper which seems to do a file level copy but still support folder hard links.

Here's my problem. My new disk is formatted as Journaled HFS+. When I run "Backup all files, erase then copy" the first thing SuperDuper does is reformat the drive as HFS+ without the journaling. It then spends 3 hours happily copying files across before it hits the first folder hard link and dies with the message:

"Error | SDCopy: Attempt to create hard link on /Volumes/Vault but file system format does not support hard links. Please enable HFS+ Journaling with Disk Utility and try again."

I've tried this a couple of times now to confirm that SuperDuper really is disabling the journaling itself. The last time I even used Disk Utility to turn journaling back on shortly after SuperDuper started copying files. That seemed to work but SuperDuper still dies with the same error message even though journaling *is* enabled. I guess SuperDuper is caching the journaling status not expecting someone to change it mid-backup.

So what can I do to convince SuperDuper to proceed? Can I force it to turn journaling on when it reformats the drive? Can I get it to do the backup without reformatting the drive at all?

You'll want to use "Smart Update", which won't format the destination, and thus will retain the original format (rather than updating it to match the source's format).

It seems Smart Update is only available to registered users. I've absolutely no problem with paying for the software if it works. But I was hoping to get at least one successful backup done to test the software before paying.

Well, turn on journaling for the source, then. You should be able to using Disk Utility.

Nope. The source is read only which is preventing it.

Well, as soon as SD! finishes erasing the destination, you can quickly turn Journaling on. That should work.

Sorry. I've already tried that.

Sorry, missed that. I'm not sure what else to suggest here, rich. If the volume is, in the end, damaged, it's unlikely we'll be able to copy it even if you get journaling on.

I ended up buying SuperDuper and using Smart Update which worked perfectly.

It's very frustrating when a long running task, such a backup, fails after several hours. So I would like to suggest an improvement to prevent other customers from being bitten by this type of failure. When SuperDuper is copying a time machine archive it should check that the destination volume will be HFS+ journalled at the start of the copy and if it is not then either:

1) Fail early. So that the failure takes seconds not hours
2) Enable journalling on the destination volume. This could be automatic, a preference setting, or after a prompt.

Another thing that would have helped is if SuperDuper recognised that I had manually enabled journalling via Disk Utility part way through the backup. Rather than insisting that journalling was off when it was actually on.

Anyway, just some ideas.

Thanks,

- Richard

We actually don't know Journaling will be required until we get to a hard linked folder, which requires Journaling to be on to do... that's why we can't warn you ahead of time.

It's my understanding that hard linked folders will only ever exist inside a time machine backup. Certainly there is no way I can see for a user to create folder hard links* via the finder or terminal. Also, any time machine backup with more than one snapshot in it will almost certainly contain folder hard links. So it seems to me that checking for the existence of a time machine backup is almost exactly equivalent to checking for folder hard links.

Alternatively, If you don't like the idea of checking up front maybe SuperDuper could try to turn journalling on when it hits a hard linked folder instead of just throwing an error.

* Which makes we wonder how SuperDuper does it.

It was something we considered doing, but since Smart Update can resume the update relatively quickly it didn't have sufficient upside to justify the logic involved, but it's still on the list of potentials.