Under certain circumstances, your virtual servers that are offline might be implicitly cold migrated to another compute resource within one compute zone. This occurs after manual start up with no additional information in the logs, when the compute resource cannot provide sufficient resources for the VS or is offline. If the compute resource is offline or OnApp considers that there are not enough resources to start the VS, usually because there is not enough free RAM available, the VS is implicitly cold migrated to a compute resource with sufficient resources and started there.
The mentioned conditions may also appear if a compute resource was rebooted, then came back online, but the information about its free and total RAM has not yet been obtained from the compute resource and you attempt to start up the VS. In such a case, OnApp considers that the compute resource does not have sufficient resources and migrates the VS.
To avoid such behavior, check the compute resources list at Control Panel > Settings > Compute Resources to see whether a compute resource you are interested in is online and actual information about its RAM is displaying. If there is enough free RAM for the VS, starting the virtual server will be done on the checked compute resource.