Typical DNS propagation to Rackspace name servers (globally) may take up to one minute. This refers to the amount of time it takes after a change (add/delete/update) is made to a customer's records via API, DNS Manager, MyRackspace Customer Portal, Cloud Control, and so forth before the change is live on our name servers.
A large amount of changes made simultaneously may take 2-3 minutes. If a new domain is added or an existing domain is deleted, this may take up to a few minutes to propagate to our Rackspace name servers. When changing name servers for a domain, complete propagation will take about 2 days for most domains; this is enforced by the registries.