DDD removal statistics

In BMC Atrium Discovery systems where discovery (or consolidation) is in progress for most of the available time, contention between the removal (aging out) of DDD nodes (in this case DiscoveryAccess nodes and their children) and the creation of new nodes, may affect the performance of in-progress discovery runs. From BMC Atrium Discovery 8.3 SP2 you can avoid this performance impact by scheduling DDD removal blackout windows during which no DDD removal is undertaken.

When should DDD removal blackout windows be used?

DDD removal blackout windows should typically only be used on consolidation appliances when you need to achieve maximum discovery throughput. This is only likely to be needed at the Consolidated Enterprise scale, or possibly in the very largest scanning appliances. In virtually every discovery schedule used, the continual aging scheme used by BMC Atrium Discovery can remove "old" DDD at a similar rate as they are created.

You can determine whether scheduling DDD removal blackout windows may be beneficial using the DDD removal statistics page. The DDD removal statistics page shows the total number of DiscoveryAccesses in the datastore and those eligible for removal. If DiscoveryAccess removal is keeping up with DiscoveryAccess creation, then the number of eligible DiscoveryAccess nodes is zero, or near zero, DDD removal blackout windows are not required. If the trend of eligible DiscoveryAccess is rising over a two week period, then DDD removal blackout windows may be a solution.

See Scheduling DDD removal blackout windows page for more information.

Using the DDD removal statistics page

The DDD removal statistics page shows the total number of DiscoveryAccesses in the datastore and those eligible for removal. If DiscoveryAccess removal is keeping up with DiscoveryAccess creation, then the number of eligible DiscoveryAccess nodes is zero, or near zero, and the continual DDD aging scheme is sufficient. See example 1 in the diagram below.

With the continual DDD aging scheme in operation, if the trend of eligible DiscoveryAccesses is rising over a two week period, you may have contention between the DDD creation and removal processes. See example 1 in the diagram below. In this scenario you may find that using DDD removal blackout windows to schedule removal between the gaps in your discovery schedule may give you better overall system performance. Once you have set up DDD removal blackout windows you should continue to monitor the DDD removal statistics page to ensure that removal is keeping up with creation. See diagrams 3 and 4 in the diagram below.


Viewing DDD removal statistics page

To view the appliance performance page:

  1. Click the Administration tab from the primary navigation bar.
  2. Click the Performance icon in the Appliance section. The Appliance Performance page is displayed showing the Engines tab.
  3. Click the DDD Removal tab.

The DDD removal statistics page shows the total number of DiscoveryAccesses in the datastore and those eligible for removal for the last 28 days.

This screen illustrates DDD Removal Statistic on the Appliance Performance page.

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