Before deploying any virtual appliance, make sure that you following these sizing guidelines In previous releases, sizing guidelines were provided by defining classes of appliance deployment. The introduction of Big Discovery means that these classes are no longer valid for clustered deployments. The earlier sizing guidelines do still have some relevance for single appliance deployments, but where scale is required, just add hardware!
If RAM is available, the OS uses some as a filesystem cache which dramatically improves datastore performance. As datastore files grow then a correspondingly large increase in RAM is required to maintain levels of performance. In many cases, the datastore files are very large, of the order of 10 to 100 GB. For example, for a large datastore, performance improvements have been seen by increasing RAM from 32 GB to 128 GB and further still to 256 GB.
The appliance specification page in the UI retains the classes for standalone deployments, but not in clusters. We are reviewing BMC Discovery performance as version 10 is deployed, and might extend our recommendations based on our customers' real experiences.
Dedicated VMware Resources
BMC recommends that the CPU and RAM resources that are allocated to the BMC Discovery appliance are reserved, and are not shared with other VMware guest operating systems. Otherwise, performance might be inconsistent and might not achieve expectations. For more information, contact your VMware administrator.
For more information on the previous recommendations, see Sizing guidelines in the version 9.0 documentation.