A backup task hangs. The task's progress stays at 0 percent for days. Domains are left suspended if the backup task was set up to suspend domains for the duration of the backup process. No errors are reported in the backup log files.
However, a backup of the server configuration only (without content) finishes without problems.
The problem is caused by a product error in Plesk 11.0.9 Micro-Update #52.
# pkill -9 -f mysqldump
# pkill -9 -f plesk_agent_manager