# Limitations

* **Connection Limits:** The maximum concurrent connections applicable is based on total cluster memory. The connection limit is based on: **(RAM in GB − 2 GB system reserve) / 2 = max connections (in thousands)**. For more information, see [<mark style="color:blue;">Formula for Maximum Connections</mark>](https://docs.ionos.com/sections-test/guides/databases/mongodb/sizing#tune-connections-and-pools).
* **CPU:** The total upper limit for CPU cores depends on your quota. A single instance cannot exceed 31 cores.
* **RAM:** The total upper limit for RAM depends on your quota. A single instance cannot exceed 230 GB.
* **Storage:** The upper limit for storage size is 4 TB.
* **Backups:** Storing cluster backups is limited to the last 7 days. Deleting a cluster also immediately removes all backups of it.
* **IP Ranges:** The following IP ranges cannot be used with our MongoDB services:
  * `172.16.0.0/12`
  * `192.168.230.0/24`
  * `10.208.0.0/12`

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**Note:** To scale resources in the **Enterprise** edition, contact [<mark style="color:blue;">IONOS Cloud Support</mark>](https://docs.ionos.com/cloud/support/general-information/contact-information).
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