Fastest backup destination will be either Local storage (provided that it's on a separate device), or remote SSH destination (provided that the bandwidth is very high and fast).
For best performance, it is also recommended to exclude files/folders, and disable backup for suspended accounts.
Incremental backups will copy only files that have changed or are new since the last full backup.
If you activated 'backup retention' JetBackup will create a "point-in-time incremental backups", in which will use as little space as possible (using hardlinks). So a 30 days backup retention, of a 2GB file/directoryt backup, will only consume 2GB + 30 Days of new/changed files (** At the moment, mysql is fully dumped, as it doesn't support incremental backups).
For best performance, it is recommended to use a server that is dedicated only to backups, and not a web server that also holds your backups or uses a separate HD device for backups if your backups are local.
The incremental backup feature with Amazon backup destination is limited to your backup rotation. For example, if we set a 7 day backup rotation, backups will be copied in full 7 times for each backup rotation. Once you’ve reached the 7th backup rotation day, you will start over again from the 1st, this time it will be incrementally, backing up only changes made in the last 6 days, and so on...
JetBackup has an email notification system in which you can get email alerts for various jobs/actions/errors in JetBackup.
To set up email notification system navigate to Settings -> Notification.
To get more informative details about what exactly happened, you can also manually review the logs. The logs are available at Logs section, or from the server's CLI at "/usr/local/jetapps/var/log/jetbackup".
/var/log/secure
[root@localhost ~]# tailf /var/log/secure
Jul 29 13:07:11 localhost root: JetBackup authentication failed using password for newuser from 192.168.1.100 - Invalid username
Jul 29 13:07:18 localhost root: JetBackup authentication succeed using password for testuser from 192.168.0.101
Jul 29 13:07:30 localhost root: JetBackup authentication succeed using password for root from 192.168.1.101
Jul 29 14:15:04 localhost root: JetBackup authentication succeed using password for root from 192.168.1.111
Jul 29 14:52:10 localhost root: JetBackup authentication failed using password for acct01 from 192.168.0.2 - IP not whitelisted
Jul 29 14:52:33 localhost root: JetBackup authentication failed using password for acct02 from 192.168.1.1 - IP not whitelisted
Occasionally there will be an issue with the activation process.
You will need to refresh your JetBackup license if you receive the error "Error while trying to validate your License: No JetBackup license was found for the IP x.x.x.x" when your license is verified as being in 'Active' or 'Reissue' state via: https://www.jetapps.com/verify-license
To force JetBackup to validate your license against our licensing servers please execute the following command from your server's CLI as root user
jetcli backup --license