You can use the NetBackup Resource Limit dialog to control the number of simultaneous backups that can be performed on a VMware resource type. The settings apply to all NetBackup policies.
For example, to avoid overloading the ESX server, you can place a limit on the number of concurrent backup jobs per ESX server. To control I/O overhead on the datastore's array, you can limit the number of concurrent backups per datastore.
The Resource Limit screen applies only to policies that use automatic selection of virtual machines (Query Builder). If virtual machines are selected manually on the Browse for Virtual Machines screen, the Resource Limit settings have no effect.
To limit the number of simultaneous jobs per policy, use the Attributes tab. The effect of this option depends on how the policy selects virtual machines.setting on the policy
To set limits on the use of VMware resources
In the NetBackup Administration Console, click Host Properties > Master Servers and double-click the NetBackup master server.
In the Properties screen, scroll down in the left pane and click Resource Limit.
Click in the Resource Limit column to set the maximum NetBackup usage for the resource type. The settings apply to all policies.
For each resource type, the default is 0, (No Limit). A resource limit of 4 for datastore means that NetBackup policies can perform no more than four simultaneous backups on any particular datastore.
Table: Resource types and limits describes the limits:
Table: Resource types and limits
Other resource-related considerations may be of interest.