Problem

After building a makeshift Time Capsule using Debian Linux and parts I had lying around — a Raspberry Pi and Thermaltake BlacX hard drive dock — there were numerous intermittent problems and ultimately misleading error messages like:

• The identity of the backup disk has changed
• The backup disk is not available
• Sparse bundle could not be accessed
• The OS X system.log showed “sock_settclassopt got error 57”

Discussion

These errors were not consistent, and would mysteriously disappear after I rebooted both the Raspberry Pi AND the OS X 10.8.2 Macbook, but not either independently.  It seemed as if i could get one good backup after both rebooted, but then all bets were off.

Solution

All of these intermittent problems went away completely when I changed the power supply on the Raspberry Pi to a Gmyle 1A adapter instead of trying to power it from a random USB port.  Also, some suspiciously thin USB cables were replaced with standard USB 2.0 cables.  Now the FrankenCapsule works flawlessly — and it’s attached to a UPS so as not to encourage any filesystem inconsistencies.

Power supply issues can cause strange behavior.