How the events are generated
When you configure disk pools in NetBackup, NetBackup connects to the DFM server through the NetApp NetBackup plug-in. The plug-in scans the volumes that are not protected and takes some time to find out the details of unprotected volumes. If the master server asks for the event list while the event list is being prepared, then the same master server who triggered this does not receive the events at that time. However, the master servers which connect to the DFM server after the event list is prepared receive those events. After every 24 hours from the time the first call is made, the current list of events are sent again to all master servers that are connected to this DFM server. Currently this is a fixed cycle unless NetBackup is restarted. Maximum eight event channels are supported by default which means that maximum eight master servers are capable of receiving events from DFM. If more than eight master servers are connected to the DFM server and all are monitored by OpsCenter then it is not predictable which eight master servers receive those events.
The value for maximum number of event channels is configurable in a file on the NetBackup plug-in host (usually the same as DFM host):
Windows | C:\Program Files\netapp\NBUPlugin\config\NBUPlugin.cfg |
UNIX | /usr/NetApp/NBUPlugin/config/NBUPlugin.cfg ([ NBUPlugin:NumEvCh ] Value=8) |
It is recommended that the value for maximum event channels is configured as 8. Increasing the value may affect the DFM performance.
Consider a scenario where one master server is connected to one DFM server and is monitored by OpsCenter. When NetBackup initially connects to the NetApp NetBackup plug-in, then it does not receive any event until the complete cycle of 24 hours assuming that the event cycle is of 24 hours. After 24 hours, the events are sent to OpsCenter by NBSL. So even if the condition like Volume almost Full has occurred, you see events only after the cycle is complete.
Consider a scenario where multiple master servers monitored by OpsCenter are connected to one DFM server. In this scenario, the first master server that connects to the DFM server by NetApp NetBackup plug-in never receives the event for the first cycle. The master servers which connect later receive events only if they are connected after DFM prepares the event list. No events are sent in the time between when the first master server connected to DFM server and the time DFM is ready with events. If some master server connects during that time then it does not receive any events. Which master servers receive the events depends a lot on when they connect to the NetApp NetBackup plug-in. But after 24 hours, all master servers should receive the events from NetApp NetBackup plug-in provided that maximum eight master servers are connected.