We have a Plesk 9.5.4 server with 2423 domains and according to SELECT * FROM psa about 8811 e-mail accounts.
When we do a backup it takes about three days and the backup file is about 65 GB big.
We need a long term strategy for disaster recovery to solve this problem of long restores. If I restore a 65 GB file that takes three days my clients would leave me in droves. What can I do?
If you have only a single server running your service(s), it may not be feasible to avoid high down times in case of disaster.
The best you can do is to have another server for higher availability. Then, the appropriate replication mechanisms should be applied to keep both server in sync. When a disaster occurs, you will be safe by failing over to the second server.
For the backup process, you need to make full backup. Then, differential/incremental backups should be enough. I am not sure if there is such option in your control panel.