You might want to contact their support - he is really good at answering.
i don't use Time machine, so I can only guess and my guess would be that two different backup programs running at the same time could easily cause a problem.
I was passed to a Senior Technician. When he learned that I also use Carbon Copy Cloner (currently version 3.4.4) he told me that Apple has been getting a lot of complaints that CCC corrupts Time Machine backup files. When I asked further, he advised that this is a relatively recent development, over the past several iterations of System X.
I would have to concur with baltwo's assessment of that tech. There's no problem with CCC and Time Machine. I've been using both to maintain several separate backups for years, and have never had a problem as a result. How are you using CCC?
Unfortunately, it is a simple fact of life that backups can become corrupt, and often that is not discovered until the very moment you need the backup the most. That's one big reason to keep multiple backups, made with two different backup programs.
CCC goes to great lengths to avoid all Time Machine business for file-level copies. If you were to clone any other volume to a Time Machine volume, the Backups.backupdb folder is explicitly protected from any modification whatsoever. CCC also won't copy the contents of a Backups.backupdb folder if you were to clone the Time Machine volume to some other volume -- I explain why that is here in the documentation:
The only scenario in which CCC will copy a Time Machine volume is when you ask for a block-level copy, and in that case, the entire volume -- bit-for-bit -- is copied precisely to the destination volume. To this day, I've never received a single report of potential corruption of Time Machine "files". I've received several reports where people came to me with corrupted Time Machine backups and they hoped that CCC could help them get out of the mess, but never a suggestion that CCC was involved in the corruption. Given the lengths I go to to avoid modifying TM backups, I certainly wouldn't expect there to be a correlation.
I'll follow up with AppleCare on these other purported complaints to see if there's any meat to that. If there's a real issue here, I'll deal with it immediately, but I think it's more likely that the corruption of your TM backup (or the restore mechanism -- it isn't clear which is broken) is unrelated to your use of CCC.
Bombich Software, Inc.
Randy Knowles wrote:
. . .
he told me that Apple has been getting a lot of complaints that CCC corrupts Time Machine backup files. When I asked further, he advised that this is a relatively recent development, over the past several iterations of System X.
I also think this is malarky.
I use CCC and TM, as do many people, have spent lots of times on these forums, and have never heard of it. In my setup, my Mac wakes up early in the morning to update my CCC clone, and a TM backup usually runs at the same time.
The way CCC finds what's changed and needs to be backed-up does take much longer than TM usually does, and uses a considerable amount of CPU - - your Mac may slow down noticeably, and if a TM backup is also running, well, it may slow down, too. But won't cause corruption.
If both are running to the same disk drive (not a good idea), they'll both run slower, partly beacuse they both need some CPU, but mostly because all the data is squeezed into the same "pipe." But again, no corruption.
My only advice would be to avoid running both at the same time if they're going to be large backups (ie, after an OSX upgrade or other massive changes) -- but just because you may find other things running rather slowly.
Thanks to baltwo, Thomas Reed and Mike Bombich for your repllies. I'll try to clairfy how I have been using CCC. My internal hard drive normal boot partition is named "Macintosh HD". Of course I also have the Lion recovery partition, as well as a Boot Camp partition.
I currently have a Seagate Go Flex Desk for Mac 2 TB Firewire 800 external (Seagate model STBC2000100). I put several partitions on this drive when I first bought it in order to move over the contents of several different previous older Firewire 400 drives from my old Mac mini. Time Machine backs up to the partition named "(c) miniStack 500" (not bootable). CCC backs up to the partition named "Boot B-U Macintosh HD" (bootable).
The Boot B-U Macintosh HD partition is dedicated solely for the CCC backup and tests ok as a startup volume using option restart. I have been doing clone backups of "Macintosh HD" to "Boot B-U Macintosh HD" using the standard default settings, which I am under the impression does not do block copying, but rather file copying. My intention was to thus run the 2 different back up systems (CCC and Time Machine) completely independently.
I hope this clairifies what I have been doing, and thanks again for your replies.
Linc - Thanks for your reply. Initial attempts to restore using Time Machine repeatedly failed, all at the same spot (place and lenght of time into the attempted restore). We tried to restore using Time Machine from several different previous dates, both before and after the Software Update hang, all with the same failure result.
That is when Apple Technical Support concluded the Time Machine backup files are corrupted.
Thanks again. - Randy
Randy Knowles wrote:
. . .
Time Machine backs up to the partition named "(c) miniStack 500" (not bootable). CCC backs up to the partition named "Boot B-U Macintosh HD" (bootable).
That should cause no problems at all (other than possible minor slowdowns if both run at once).
The only downside to that is, you've got all your backup "eggs" in one basket -- the Seagate. When it fails (and they all do, sooner or later), you may lose both backups. It's rare, but there are threads in this forum where an internal HD failed, and a restore was just getting started when BAM! the backup drive failed, too.
For best results, use a different drive (preferably a portable) to make periodic backups, and take it to a secure off-site location, such as your safe deposit box, workplace, relative's house, etc. That way, you're also protected against fire, flood, theft, etc., as well as failure of the Seagate.
Pondini - Thanks for your reply. Until now I had not made any effort to avoid both Time Machine and CCC running at the same time. Time Machine is on auto pilot, whereas I had been doing CCC manually. However, doing CCC manually I had been negligent in not running it often enough. My last CCC backup before the Software Update hang was way back on September 16h.
I'm thinking that, if I resolve this question about corruption of TM by CCC, I should set up CCC to run automatically as well. If both TM and CCC run automatically, how does one prevent them from running at the same time?
Thanks again for your comments. - Randy
Pondini - Wow, you know I have just been thinking about that, too! I have just started investigating getting another external HD or perhaps a remote backup service via the web? Or maybe both in order to address your suggestion about a backup being stored off site.
I know nothing about backup off site via the web. How reliable is it? Would I get my normal speed (3.28 Mbps upload) using such a service? How expensive do such things run? Any other comments would be appreciated.
Thanks again! - Randy