Time Machine - for reliability, new backup

[PeterJP]

Yesterday, my MacBook Pro gave me the message that for reliability reasons, Time Machine should make a new backup. In short, it means that all the backups I had before had become worthless and that I should start all over. I thought that was quite worrying for a backup tool.

I found this thread that spans 25 pages over 2 years on Apple's support site. No solution yet: https://discussions.apple.com/thread/3684176 It turns out the error also appears on Apple's own Time Capsule. I didn't find a thread on this topic on this forum, that's why I'm posting one now.

If anybody has a workaround, that would be helpful. I'd rather not use a USB disk. My backup target is a home-built NAS that presents itself as a Time Capsule to my Mac.

 

[maflynn]

TM found issues in checking the backup and so you have a choice, stop backing up there, to retain history, or do what TM is recommending, start a new backup.

Since you're on a NAS, you can perhaps define a new shared drive to use as a Time Machine backup thus saving your old stuff and maintaining a current backup.

FWIW, I ran into this issue often using a NAS, and have moved by TM backups to a DAS. I believe it had it had to do with some issues with the NAS' implementation of AFP. After getting that error message a handful of times over the months, I opted for the DAS

 

[PeterJP]

Maflyn,

Yes, it seems that Apple's approach of how it stores the TM files is the issue. Maintaining a virtual disk image over a network seems hard, let alone over Wi-Fi.

I also switched to DAS, though very, very reluctantly. I had to disassemble my backup PC that I had in the cellar, take out the hard drives and now I also need a DAS backup solution for my fixed PC.

 

[smirk]

I used to get corrupt sparse bundles every time my Mac went to sleep during a backup. Most of the time, I was able to repair the damage by following these instructions:

http://www.garth.org/archives/2011,...ine-sparsebundle-nas-based-backup-errors.html

But invariably it makes you start to question the integrity of your backups. If my Mac's hard drive fails and I have to recover everything out of Time Machine, will everything be there? I have had to adjust my thinking -- instead of thinking of Time Machine as version control, I now think of it as just a backup. That way it doesn't sting so much when you have to delete the Time Machine archive and start over.

P.S. Make sure you keep up to date on your Netatalk installations. Ubuntu is still on Netatalk 2, I believe, but Netatalk 3.0.8 is the most recent version, with more features and bug fixes. You will have to install from source instead of using apt-get or the software center.

P.P.S. I recently added another level of backups to my setup (I also have a home-built server). Besides the hourly Time Machine backups I also now use Carbon Copy Cloner to back up to an image file on the server. It only saves changed files so backups are fast after the initial one. So the server holds a nightly full-disk backup as well as Time Machine data -- and those two are stored on separate drives in the server. A little extra security at the cost of some disk space.