Although SpiderOak ONE and Groups are able to back up most any file, we do have best practices for encrypted volumes. The preferred method is to treat it like a USB device or a virtual machine: mount the encrypted volume and back up the files inside it. This is for several reasons.
Encryption thwarts deduplication, so every time you make any trivial change to any file inside your encrypted volume, the entire volume changes and every bit has to be uploaded again. Good encryption looks like perfectly random data, and deduplication requires identifiable repeating data. That's why we deduplicate your files before we encrypt them, and why we likewise suggest that you let us deduplicate them before you encrypt them.
File size is another matter. Many encrypted volumes exceed the 10 GB maximum that we recommend for a single file. If you back up the files inside the volume, then you are less likely to run into this limitation.
You also want to avoid SpiderOak backing up a file while "hot", or still being written to. Some users who back up entire encrypted volumes have reported that the resulting backup is corrupt because the volume was still in the process of being encrypted when it was backed up. Such a backup file is unrecoverable.
To avoid all these difficulties, our recommendation is to mount the encrypted volume, then back up the files inside it.