When the Center is turned off
The Agent does not wait for the Center: when the time comes, it backs up, encrypts and keeps the files in its spool.
The schedule is signed and stored on the Agent
Each time you save a schedule on the Center, the Center signs the plan with its private key and sends it to the Agent. The Agent only runs plans with a valid signature and keeps the old plan until it receives a new one — so even if the Center is off for a week, the Agent still runs on time.
Where the spool lives
| Connection method | Spool |
|---|---|
| 1 and 2 | Spool folder on the Agent machine (default %ProgramData%\SaintBackup\agent\spool). Uses up to the free space on the drive; the Agent warns when the drive is nearly full. |
| 3 (coming soon) | SaintBackup's R2 relay or your own bucket, kept for up to 60 days. |
When the Center comes back on
The Center receives the spooled backups one by one in the correct order, checks SHA-256, decrypts them and merges them into the prepared copy. A partially sent file resumes from the 8 MB block where it stopped, not from the beginning.
Incremental chain
The Agent remembers the stopping point (LSN) of the previous backup, so it continues the chain correctly without the Center. If nothing has changed, it skips the run instead of creating an empty backup.