Sub-production is any non-=production instance. Typically a ServiceNow customer will purchase a subscription and with that they are entitled to one or more sub-production instances. Production is where the subscriptions are actually used to support their organization. The sub-production instance(s) can be used for testing, development, training, etc. A key difference is that sub-production instances do not include the full Advanced High Availability (AHA) architecture that production instances include.
