By providing connection and authentication information (and an optional start time), the restore can be performed via the Tasks subsystem while the server is online. The Tasks subsystem allows you to schedule certain operations, such as import-ldif, backup, restore, start-server, and stop-server. You can schedule a restore to run as a Task by specifying the timestamp with the --task and --start options. The option is expressed in "YYYYMMDDhhmmss’" format. If the option has a value of "0" then the task is scheduled for immediate execution. You cannot run recurring tasks, so daily operations must be run using cron or through some system that can submit the task.
The backend that is being restored will be unavailable while the restore is in
progress. To specify a time in the UTC time zone, add a trailing “Z” to the
time. Otherwise, the time will be treated as a local time in the configured time
zone on the server.
$ bin/restore --task --start 20111025010000 \ --backupDirectory /path/to/backup/userRoot \ --completionNotify email@example.com --errorNotify firstname.lastname@example.org