To assure great performance, the storage API has limits in place for the number of requests and connections.
Concurrent Connections Per IP
Concurrent Uploads Per Storage Zone
Maximum FTP Connections Per IP
How are the limits applied?
The limits are applied on a server-by-server basis. What this means is each of our servers will run its own limit tracking. Essentially, connecting to two servers will then double these limits. We usually run multiple such Edge Storage API servers in each region, allowing for much higher limits in practice, allowing you to achieve much higher concurrency.
If you however continue to hit these limits, please let us know and we can increase this for you on a case-by-case basis.