Backups
Taking one, keeping it safe, and what happens when a disk fails.
A backup is a copy of everything: every student, every paper, every answer and every mark, plus the pictures used in questions.
Taking one
Settings → Backups → Back up now.
It runs in the background, so you can carry on. A large school takes a few minutes. When it finishes it appears in the list with its size.
Take one after every exam day. It costs a minute.
Getting it off the server
Press Download beside a backup. Your browser saves one file, named for the
day and time, for example opencbt-backup-2026-09-24-1640.tar.gz.
Copy that file onto a flash drive or an external disk, and keep it somewhere other than the exam hall. This is the part people skip, and it is the part that matters: a backup sitting on the exam server is no protection against the exam server failing.
Keep the last few. A backup from three exams ago is still far better than nothing, and they are small — a few megabytes per exam for most schools.
What is kept on the server
The server keeps the most recent backups by itself and removes older ones, so the disk cannot silently fill up. The list in Settings shows what is there, and how much room is left.
When you need one back
Restoring replaces everything with the backup's contents, so it is not a button in the app: it is a command, run with openCBT stopped, by whoever looks after the machine. Send them the backup file and this page: restoring a backup.
Two things to tell them:
- Take a fresh backup first, even of a database you believe is broken. It costs nothing and it is the only way back if the restore turns out to be the wrong one.
- Anything entered after the backup was taken is gone. If a day's exams happened after it, those results go with it.
What a backup does not protect you from
- A lost flash drive. The file is not encrypted; whoever holds it can read the school's data. Keep it as carefully as you keep a paper script.
- Deleting something on purpose. A deleted paper is deleted in every backup taken afterwards. The audit trail records who deleted what, but only a backup from before the deletion brings it back.