Block Storage is a type of IT architecture in which data is stored as a file system. It provides endless possibilities for storing large amounts of information. It guarantees the safety of resource planning systems and provides instant access to the required amount of data without delay.

IONOS provides you with several ready-made public images that you can use immediately. You can also use your own images by uploading them via our FTP access. For more information, see Private Images. Your IONOS account supports many types of HDD images as well as ISO images from which you can install an operating system or software directly, using an emulated CD-ROM drive.

Storage types and options

The virtual storage devices you create in the DCD are provisioned and hosted in one of the IONOS physical data centers. Virtual storage devices are used in the same way as physical storage devices and can be configured and managed within the server's operating system.

A virtual storage device is equivalent to an iSCSI block device and behaves exactly like direct-attached storage. IONOS block storage is managed independently of servers. It is therefore easily scalable. You can assign a hard disk image to each storage device via DCD (or API). You can use one of the IONOS images, your own image, or a snapshot created with DCD (or API). You have a choice of hard disk drive (HDD) and solid-state drive (SSD) storage technologies while SSD is available in two different performance classes. For more information about setting up the storage, see Set Up Storage.

Up to 24 storage volumes can be connected to a Dedicated Core Server or a Cloud Cube (while the Cloud Cube already has one virtual storage device attached per default). You can use any mix of volume types if necessary.

IONOS Cloud provides HDD and SSD block storage in a double-redundant setup. Each virtual storage volume is replicated four times and stored on distributed physical devices within the selected data center location.

HDD storage

The following performance and configuration limits apply per HDD volume. The performance of HDD storage is static and independent of its volume size.

HDD storage performance

  • Read/write speed, sequential: 200 Mb/s at 1 MB block size

  • Read/write speed, full random:

    • Regular: 1,100 IOPS at 4 kB block size

    • Burst: 2,500 IOPS at 4 kB block size

HDD storage limits

  • Minimum Size per Volume: 1 GB

  • Maximum Size per Volume: 4 TB

Larger volumes can be made available on request. For more information, contact IONOS Cloud Support.

SSD storage

SSD storage volumes are available in two performance classes - SSD Premium and SSD Standard. The performance of SSD storage depends on the volume size. Find the respective performance and configuration limits listed below.

SSD Premium storage performance

  • Read/write speed, sequential: 1 Mb/s pro GB at 1 MB block size

  • Read speed, full random: 75 IOPS per GB at 4 KB block size

  • Write speed, full random: 50 IOPS per GB at 4 KB block size

SSD Premium storage limits

  • Minimum Size per Volume: 1 GB

  • Maximum Size per Volume: 4 TB

    • Maximum Read/write speed, sequential: 600 Mb/s per volume at 1 MB block size

    • Maximum Read speed, full random: 45,000 IOPS at 4 KB block size and min. 4 Cores, 4 GB RAM per volume

    • Maximum Write speed, full random: 30,000 IOPS at 4 KB block size and min. 4 Cores, 4 GB RAM per volume

Larger volumes can be made available on request. For more information, contact IONOS Cloud Support.

SSD storage performance

The performance of SSD storage is directly related to the volume size. To get the full benefits of high-speed SSDs, we recommend that you book SSD storage units of at least 100 GB. You can use smaller volumes for your VDC, but performance will be suboptimal, compared to that of the larger units. When storage units are configured in DCD, expected performance is predicted based on the volume size (Inspector > Settings). For storage volumes of more than 600 GB the performance is capped at the maximum as specified in the documentation above.

Availability Zones

Secure your data, enhance reliability, and set up high-availability scenarios by deploying your Dedicated Core Servers and storage devices across multiple Availability Zones.

Assigning different Availability Zones ensures that redundant modules reside on separate physical resources at IONOS. For example, a server or a storage device assigned to Availability Zone 1 resides on a different resource than a server or storage device assigned to Availability Zone 2.

For HDD and SSD Storage, you have the following Availability Zone options:

  • Zone 1

  • Zone 2

  • Zone 3

  • A - Auto (default; the system automatically assigns an Availability Zone upon provisioning)

The server Availability Zone can also be changed after provisioning. The storage device's Availability Zone is set on first provisioning and cannot be changed subsequently. However, you can take a snapshot and then use it to provide a storage device with a new Availability Zone.


The first time you create a storage unit based on a public image, you must select at least one authentication method. Without authentication, the image on the storage unit cannot be provisioned. The authentication methods available depend on the IONOS operating system image you select.

Authentication methods depend on the operating system.

Authentication methodsSSH keyPassword

IONOS Linux images



IONOS Windows images



We recommend using both SSH and a password with IONOS Linux images. This will allow you to log in with the Remote Console. It is not possible to provision a storage unit with a Linux image without specifying a password or an SSH key.

Passwords: Provisioning a storage device with a Windows image is not possible without specifying a password. It must be between 8 and 50 characters long and may only consist of numbers (0 - 9) and letters (a-z, A - Z). For IONOS Linux images, you can specify a password along with SSH keys, so that you can also log in without the SSH, such as with the Remote Console. The password is set as the root or administrator password with corresponding permissions.

SSH (Secure Shell): To use SSH, you must have an SSH key pair consisting of public and private keys. The private key is installed on the client (the computer you use to access the server), and the public key is installed on the (virtual) instance (the server you wish to access). The IONOS SSH feature requires that you have a valid SSH public/private key pair and that the private key is installed as appropriate for your local operating system.

If you set an invalid or incorrect SSH key, it must be corrected on the side of the virtual machine.


IONOS is focused on ensuring the uninterrupted and cost-efficient operation of your services. This is why we offer a selection of tested operating systems for immediate use in your virtual cloud instances. To ensure uninterrupted, secure, and stable performance, all operating systems, regardless of their source, should meet the following requirements:

  • VirtIO drivers are essential for the operation of virtual network cards.

  • The following are the recommended drivers for the operation of virtual storage:

    • VirtIO (maximum performance)

    • IDE (for vStorage, an alternative connection by IDE is available, but it will not deliver the potential performance offered by IONOS).

    • QXL drivers are required to use the Remote Console.

  • We guarantee operation for the selected operating system as long as vendor or upstream support is available.

  • In general, all current Linux distributions and their derivatives are supported.

  • Microsoft Windows Server versions are also supported as long as vendor support is available.

The older an OS version, the greater the risk of performance and stability losses. It is recommended that you always switch to the current versions well before the manufacturer's support for your old version expires. This will greatly improve your operating system's security and functionality.

When operating software appliances, it is recommended that you use the images that have been specially prepared for the KVM hypervisor.

If you are using special software appliances or operating systems that are not listed here, contact IONOS Cloud Support. We would be happy to explore the possibility of using such systems within the IONOS Enterprise Cloud and advise you on the best possible implementation.

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