What Is It?
Block Storage provides persistent data volumes (HDD or SSD) that attach to VMs and Cubes. Volumes persist independently of the VM lifecycle, can be detached and reattached to different servers, and are encrypted at rest with AES-XTS 256-bit keys. Choose from HDD for bulk storage or SSD Standard/Premium for performance-sensitive workloads.
Quick Facts
| Aspect | Details |
|---|---|
| Types | HDD, SSD Standard, SSD Premium |
| Capacity | 1 GB - 4 TB per volume (larger volumes on request) |
| Encryption | AES-XTS 256-bit at rest (automatic), unique key per volume |
| Driver | VirtIO (recommended), IDE (fallback) |
| Hypervisor | KVM/libvirt |
| Secure Deletion | Metadata zeroed within 48 hours, encryption key destroyed |
Performance Specifications
| Class | Sequential I/O | Random Read IOPS | Random Write IOPS | VM Requirements |
|---|---|---|---|---|
| HDD | 200 MB/s (static) | 1,100 regular, 2,500 burst | Same as read | None |
| SSD Standard | 0.5 MB/s × GB (max 300) | 40/GB (max 24,000) | 30/GB (max 18,000) | ≥2 cores + 2 GB RAM |
| SSD Premium | 1 MB/s × GB (max 600) | 75/GB (max 45,000) | 50/GB (max 30,000) | ≥4 cores + 4 GB RAM |
Performance scales with volume size. IONOS recommends ≥100 GB per SSD volume for optimal throughput. Volumes >600 GB cap at maximum values.
Choosing Your Storage Type
Choose HDD when: Backups, archives, cold storage, low-cost bulk data where performance is not critical.
Choose SSD Standard when: General workloads needing better performance than HDD without top-tier speed requirements.
Choose SSD Premium when: Databases, VMs, latency-sensitive applications requiring highest IOPS and throughput.
What You Can Do
Independent Lifecycle
Create, attach, detach, resize, and delete volumes separately from VMs. A volume can outlive multiple servers. Volumes cannot be attached to multiple servers simultaneously.
Online Resizing
Expand capacity while attached and running. No application downtime required. Volume size cannot be reduced after creation.
Availability Zone Selection
Choose availability zone during provisioning for data locality and redundancy planning. Availability zone cannot be changed after provisioning. To move a volume to a different zone, create a snapshot and provision a new volume in the desired zone.
Snapshots
Create point-in-time copies for backup or cloning. Snapshots must be managed manually and are not automatically deleted when volumes are deleted.
VirtIO Driver Configuration
Use VirtIO drivers for maximum performance. IDE driver available as fallback but delivers suboptimal throughput. VirtIO drivers required for efficient KVM/libvirt hypervisor communication.
Optional Drive-Level Encryption
Self-encrypting drives (SEDs) available for SSD Premium and Standard, adding hardware-level encryption layer beyond software encryption.
Best For
| Scenario | Storage Type | Why It Fits |
|---|---|---|
| Production databases | SSD Premium | 45,000 read IOPS, 30,000 write IOPS, guaranteed throughput |
| Web applications | SSD Standard | Balanced cost-performance, 24,000 read IOPS, cost-effective |
| Backup repositories | HDD | Low cost, adequate for sequential writes, 200 MB/s static |
| Development/testing | SSD Standard or HDD | Flexible resizing, independent lifecycle, cost options |
| High-availability workloads | SSD Premium | Lowest latency, highest throughput, critical for real-time processing |
Key Considerations
Billing & Costs
- Main billing: Per GB per 30 days
- HDD: Approximately 0.04 EUR/GB
- SSD Standard: Approximately 0.07 EUR/GB
- SSD Premium: Approximately 0.15 EUR/GB
- Additional costs: Snapshots billed separately as HDD storage, approximately 0.040 EUR/GB
Limitations
- Volume size minimum 1 GB, maximum 4 TB (larger on request)
- SSD Standard requires ≥2 cores + 2 GB RAM on attached VM
- SSD Premium requires ≥4 cores + 4 GB RAM on attached VM
- Availability zone cannot be changed after provisioning
- Cannot reduce volume size after creation
- One storage device cannot be attached to multiple servers simultaneously
- OS support guaranteed only while vendor/upstream provides support
- Performance figures assume minimum CPU/RAM requirements met
- Volumes <100 GB work but deliver suboptimal SSD throughput
Management Options
- Data Center Designer (DCD)
- Cloud API and SDKs
- Terraform provider
- Context menu operations (attach, detach, resize, delete)