[gherkin0]

>>> Everything went smoothly for about 6 months until I was updating Owncloud with a minor version upgrade, and then BAM; nobody (myself included) could decrypt any data on the server.

> Do you back up the unencrypted data though? Regardless of the viability of the raid 5 system, the raid 5 wasn't what failed. It was the encryption.

> It wouldn't have even been possible to backup the encrypted data without getting all my family members passwords too.

You could have backed up the encrypted data (+owncloud metadata) in its encrypted form. Then, when you ran into the bug that corrupted the main copy of the encrypted data, you could have restored the old backup of the encrypted data and reverted to the last working version of Owncloud to access your data.