Sizing guidelines

The following guidelines are based on typical deployments in the field, and are intended to serve only as recommended configurations for your environment.

This section defines four "classes" of appliance deployment that broadly follow how BMC Atrium Discovery is deployed in the field. They are differentiated by how many Operating System Instances (OSIs) that are being scanned by BMC Atrium Discovery. The names given to these classes are of use only in this document and do not relate to the various editions that BMC Atrium Discovery is available in.

The classes are:

  • Proof of Concept. Small, time-limited test deployments of BMC Atrium Discovery, scanning up to 150 OSIs.
  • Baseline. A typical baseline as offered by BMC. Scanning up to 500 OSIs.
  • Datacentre. A typical large scale deployment. Scanning up to 5000 OSIs.
  • Consolidated Enterprise. Enterprise scale deployments, typically a Consolidation Appliance taking feeds from many Scanning Appliances. Typically scanning or consolidating up to 20000 OSIs, though at these levels, a weekly scanning or focused scanning strategy may need to be adopted.

Proof of Concept

The Proof of Concept class has minimal storage allowance as they are only intended for a limited period of scanning such as a week long trial. For longer periods or a continuously used development or UAT system, the Baseline class is the minimum recommended.

Memory and swap considerations

The recommended figures for memory provide a good level of performance in typical scenarios. The upper level should not be considered a limit, BMC Atrium Discovery will make use of available memory. You can determine whether additional memory is needed in your appliance by monitoring swap usage.

The recommended figures for swap can be exceeded, there is no harm in doing so. It may prove simpler to configure the higher quantity of swap than to extend an existing swap partition as this will allow the RAM demand to be derived as above. Note that all virtual appliances are initially configured with 8 GB swap.

A 32 bit appliance cannot be used in any deployments requiring more than 4GB RAM. In practice this means that any deployment beyond a proof of concept must use a 64 bit appliance. The memory limit for a 32 bit appliance can be lower than 4GB depending on your environment.

Memory and swap usage

Memory and swap usage depends on the nature of the discovery being performed, with Mainframe and VMware (vCenter/vSphere) devices requiring more than basic UNIX and Windows devices.

Impact of Appliance Snapshot

The BMC Atrium Discovery Appliance Snapshot feature allows you take a snapshot of the datastore and critical configuration files to facilitate moving the data between appliances.

The process by which the data is packaged means that a considerable overhead of empty disk space is needed to complete the task.

Therefore, when providing guidelines for how much disk space to give your Virtual Appliance for the database, you must first decide whether you intend to perform Appliance Snapshots. If so, then you will need to provision considerably larger disks.

Where the following tables refer to CPUs, full use of a logical CPU (core) is assumed. For example, if eight CPUs are required, then you may provide them in the following ways:

  • Eight virtual CPUs in your virtualization platform, such as VMware Infrastructure.
  • Four dual core physical CPUs.
  • Two quad core physical CPUs.

Appliance sizing guidelines





Consolidated Enterprise





4 to 8


2 to 4
(see note below)

4 to 8

8 to 16

16 to 32

Swap Space

2 to 4

4 to 8

8 to 16

16 to 32

DB Disk (GB)
No snapshot




200 to 660

DB Disk (GB)
With snapshot




660 to 1500

Memory requirements for POC class

While 2GB RAM is sufficient for normal operation, but is insufficient to activate a new TKU. Attempting to activate a TKU with 2GB of RAM may take a few hours. You can increase the memory for activation and then reduce it for normal operation if required.

VMware maximums

The following are the maximum supported limits for the main deployment platforms.

  • VMWare Server v2 - 2 CPUs & 8GB RAM
  • VMWare Infrastructure 3.0.2 - 4 CPUs & 16GB RAM
  • VMWare Infrastructure 3.5 - 4 CPUs & 65GB RAM
  • VMWare Infrastructure 4 - 8 CPUs & 255GB RAM
    Note that ESX version 4 can support up to 8 vCPUs, earlier versions have a maximum of 4.
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