> For the complete documentation index, see [llms.txt](https://helpcenter.xopero.com/xopero-one-en/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://helpcenter.xopero.com/xopero-one-en/storage/cloud-storage/s3-compliant/overview-and-limitations.md).

# Overview and limitations

**Xopero ONE** supports the majority of the most popular cloud service providers compatible with **S3**:

* [x] **Xopero ONE** cloud (storage provided by **Xopero**)
* [x] **AWS** (**Amazon Web Services**)
* [x] **Wasabi**
* [x] **Azure Blob Storage**
* [x] **Backblaze B2**
* [x] **Google Cloud Storage**
* [x] other **S3** compliant

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## Configuration and limitation

Sending backup tasks to **S3** cloud storage has a limit (buffer). The default buffer value is 128 MB, which limits both the maximum data size and the minimum internet speed. If your network environment or **S3** endpoint has no additional restrictions, the minimum required upload speed is \~0.64 Mbit/s.

{% hint style="warning" %}
For cloud storage backup to **S3**-compliant systems, **Xopero** suggests a <mark style="color:$danger;">**minimum upload speed of 2.5 Mbit/s**</mark>.
{% endhint %}

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## Immutable storage

**Xopero ONE** supports **S3**-type immutable storage as a backup location. This feature is available for some of cloud storages supported by Xopero ONE (**AWS**, **Wasabi**, **Backblaze B2** and **Google Cloud Storage**). Datastores of this type allow you to freely save and read data, but modification and deletion are only possible after meeting the bucket’s retention policies.

Advantages:

* [x] Protection against ransomware and other threats (cyberattacks) – files in immutable storage are read-only and immune to loss, accidental deletion, corruption, and other issues that could compromise your data.
* [x] Prevention of accidental file deletion – when access to important or critical data is shared, the risk of deletion or modification increases, which immutable storage feature prevents.
* [x] Preservation of file authenticity – ensures data accuracy by preventing modification or manipulation of uploaded files.
* [x] Compliance with legal regulations – meets requirements for storing confidential data (e.g., payment or medical records).