Alerts are created when zombies appear on the system. These are listed in the Control Panel's Alerts screen. There are different kinds of zombies:
- Zombie Virtual Servers - VSs which are detected by the OnApp controller as currently running on a Compute resource, but which are not in OnApp's database. Also, VSs running on a Compute resource the CP is not expecting it to be running on.
- Zombie Disks - disks which are detected by the OnApp controller as existing on a data store, but which are not in OnApp's database.
- Zombie Data stores - data stores which are detected by the OnApp controller as existing in the cloud, but which are not in OnApp's database.
- Wrong Activated Logical Volumes - the virtual servers' disks that are either activated on two Compute resources simultaneously, or activated on the wrong Compute resource.
- Zombie Transactions - transactions which have running status but their PIDs do not exist on the system, or transactions that have exceeded the zombie transaction time.
The Alerts menu also lists the background processes running on your system. Max Amount values show the maximum number of background processes which can run simultaneously. Running shows the number of processes running at the moment.
In most cases, you can remove the zombie elements from the system by clicking the Delete icon next to a zombie. For further help, contact support.
In previous versions OnApp used LVM commands to detect zombie disks. Since version 4.2, the Control Panel gathers text files from the disks in the system via SNMP and makes the decision to mark certain disks as 'zombie' based on these files. This solution reduces the load on LVM. The system can gather data from a maximum of approximately 4400 disks at a time per one compute resource or backup server..