I started at a new company a while ago and did all the usual checks and measures to see how the land lies.
Backups was first. Every day we received a "Backup Complete" email, great! Backups are being done....until you look at the amount of data backed up. Approx 1GB of data was being backed up, successfully, to the single tape backup. Alarm bells started ringing, especially as the mailstore itself totals 90GB. There's no compression algo in the world that is that efficient right?!
After further investigation, it transpired that we were backing up a single database only. The database was essentially an index of what was supposed to be backed up, but not the actual files themselves. Yosemite Server Backup had decided that, despite not backing up well over 400GB of data, the fact it had backed up 1GB of an index was successful enough.....
Sorted now though, with a successful backup AND restore tests!