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Let me explain my backup strategy and the problem I am facing.

My current backup strategy:

  • Open encrypted container and execute Carbon Copy Cleaner on it at least once a week.
  • Rotate backup disks.


I have an Truecrypt partition on my 1st external hard disk. I recently found out that some files on this encrypted partition cannot be read due to bad blocks (reported by Antonio Diaz's GNU 'ddrescue').

My backup strategy is ineffective in this scenario because bad blocks are discovered during backup.

Possible strategy

  • Strategy #0: Have the encrypted partition over a RAID 1 with 2 disks.
    • Is this a suitable strategy ?
  • Strategy #1: Do you think of any other one ?


  • Mac OS X 10.8
  • External 2.5" hard disk (SATA)
  • No RAID
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Buy and run a copy of Spinrite on the disk. Spinrite does not care about the OS, encryption etc. It will just try to repair the bad sectors on a very low level.

You'll need to burn a CD from the Spinrite executable under Windows first, then boot from that CD. This boots into FreeDOS ;-) on the machine, then runs Spinrite. Have it run on level 2; or for a very thorough check, level 4.

If it manages to fix the bad sectors your issue is gone too..

After that run Spinrite once every 3 or 6 months to check for sectors deteriorating.

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