IBM Spectrum Protect (Tivoli Storage Manager aka TSM)
References to backed up files can be delete from the client, but the data is not written over.
It is possible encrypt the files on the TSM system at the client.
The TSM systems at university is level at 3 3 2 or 3 3 1. (reliabilty, unaltered, availability) The availability is not 100% for example the system is down during times of softare updates.
When the backup system is changing generation all drives and tapes are destroyed.
Please read more about information classification at Uppsala University.
On clients we use the utility KillDisk to secure deletion of block devices. If needed the drives can also be sent to destruction via the Security Division at Uppsala University or in a way approved by them.
When the servers are put out of commision the drives are sent to destruction via the Security Division at Uppsala University or in a way approved by them.