Currently Being ModeratedJan 28, 2013 3:12 PM (in response to Linc Davis)
Thank you again, Linc, for emphasising that the data might be at risk. Both these drives were reformatted in the last week (you may recall from another post the discussion about the speed of encryption - of course, in the end I just did it the prescribed way); it is worth noting that I never had backup issues prior to encyption.
I have just bought a new hard drive and will copy the Apollo data and other stuff to that (happy to start again with the TM drive once I have all my source data in two places). The files are just photos and iTunes media so file-to-file copy would give me more flexibility to put exra things on the new disk, I think, than a disk image. Now all I need to do is find a way of verifying integrity after copy and paste....
Again, thanks for everything. I'll come back when I have had time to secure all my data and then test the backup process again and see whether and how it is still failing.
Currently Being ModeratedFeb 8, 2013 4:09 AM (in response to Linc Davis)
Thanks again, Linc. Thought I'd provide an update. When I used rsync (no disk image for I wanted to flush out the corrupted files) to copy data from the misbehaving source drive to a new target drive, I kept receiving the following error:
Feb 3 23:44:47 Amarantus kernel: CoreStorageGroup::completeIORequest - error 0xe00002ca detected for LVG "Apollo" (A3619B17-9ABF-41DE-8E52-F8E32DACA169), pv D9E7EB85-2B5A-4846-95C7-ABF22444133D, near LV byte offset = 34265513984.
rsync copied all but 36 of around 13,000 files (these are recordings from CD so all replaceable). The Time Machine drive did not have any of the missing data because the previous backup had failed after it had deleted previous backups to make space for (unneceesary) large backup. Reformatted both drives using single-pass zero-out (I gather this enables the disk controller to identify and hive off bad blocks).
I now have the new drive with all my source data; reformatted Apollo has a snapshot of all my data (although I am not going to rely on this drive that was throwing errors); I am rebuilding my Time Machine backup on Chronos (encrypted; not to include the snapshot stored on Apollo).
I shall let you know if Time Machine starts kicking off unnecessary new backups at it had done originally (and which prompted this post). Again, thank you for your help above.
(By the way, to clarify and in response to your suggestion above, all external drives have been connected only directly to my MacBook Air - no hub.)