Network-Attached Volumes

Additional SSD storage volumes that can be attached to your VPS instances.

Overview

Volumes are network-attached block storage devices powered by Longhorn, providing persistent storage that can be attached to a running VPS without requiring a restart. Data survives VPS stops and restarts. Deleting a volume permanently deletes its data; non-destructive detach is not supported.

Key Benefits

Hotpluggable: Attach volumes to running VMs without downtime
Persistent: Data survives VPS stops and restarts
Flexible Sizing: 10 GB to 500 GB, expandable at any time
Replicated: Data is replicated across nodes for redundancy

Performance

Volumes use network-attached storage, which means data travels over the network between nodes. This results in different performance characteristics compared to the local NVMe root disk.

Benchmark Comparison

Metric	Root Disk (Local NVMe)	Volume (Network-Attached)
Sequential Write	~2.4 GB/s	~50 MB/s
Sequential Read	~10.2 GB/s	~75 MB/s
Interface	virtio-blk	virtio-scsi
Storage Backend	OpenEBS LVM (local NVMe)	Longhorn (replicated)

Why the Difference?

The root disk of your VPS uses local NVMe SSDs with direct access to the physical drive, delivering full NVMe speeds. Volumes use Longhorn network-attached storage, where data is replicated across multiple nodes over the network for redundancy. The current 1 Gbps network interconnect between nodes is the primary bottleneck (~125 MB/s theoretical max).

Upcoming Improvement

We are planning a 10 Gbps network upgrade that will significantly improve volume throughput, bringing speeds closer to 1 GB/s.

Recommended Use Cases

Volumes are ideal for:

Bulk data storage (media files, archives, logs)
Backup targets and data exports
Application data that doesn't require high IOPS
Extra storage when your root disk profile isn't enough

For latency-sensitive workloads (databases, caches, heavily accessed application files), keep your data on the local NVMe root disk.

Pricing

Volumes are billed at EUR 0.04/GB/month, calculated hourly.

Size	Monthly Cost
10 GB	EUR 0.40
50 GB	EUR 2.00
100 GB	EUR 4.00
500 GB	EUR 20.00

Getting Started

Creating a Volume

Navigate to Storage > Volumes in the dashboard
Click Create Volume
Choose the volume size (10 - 500 GB)
Enter a name for the volume
Select the VPS instance to attach it to
Click Create & Buy now

The volume is created and automatically hot-plugged into your running VPS. If the VPS is still provisioning, attachment waits for it to run. The volume is shown as attached only after KubeVirt confirms the disk is ready.

Using the Volume Inside Your VPS

Additional volumes use SCSI and usually appear as /dev/sda, /dev/sdb, and so on. These paths can change; the volume name in the dashboard or API is not a Linux device path.

First inspect the disks without changing them:

Bash

lsblk -o NAME,PATH,SIZE,TYPE,FSTYPE,LABEL,MOUNTPOINTS

Match the new disk to the volume's capacity and compare the device list before and after attachment. Check its filesystem, label and mount points. If several disks match, identify the correct one before continuing; do not choose by its letter alone.

You may also see a small disk, often /dev/vdb, with filesystem iso9660 and label cidata. That is the cloud-init configuration disk, which supplies VPS startup configuration. A roughly 1 MB disk with those properties is separate from the purchased data volume. Leave it intact. Size or the name /dev/vdb alone does not establish what a disk contains.

Only format a new, empty data volume. Formatting erases any existing data. Replace /dev/sdX below with the device you identified; it is intentionally not a usable default.

Bash

VOLUME_DEVICE=/dev/sdX

# Create a filesystem only on the confirmed new, empty volume
sudo mkfs.ext4 "$VOLUME_DEVICE"

# Create a mount point and mount
sudo mkdir -p /mnt/volume
sudo mount "$VOLUME_DEVICE" /mnt/volume

# Verify
df -h /mnt/volume

For a persistent mount, obtain the filesystem UUID:

Bash

sudo blkid -s UUID -o value "$VOLUME_DEVICE"

Add the following line to /etc/fstab, replacing <filesystem-uuid> with that output and checking that no entry already exists. A UUID remains valid if the device letter changes. The nofail option allows booting when the volume is unavailable.

fstab

UUID=<filesystem-uuid> /mnt/volume ext4 defaults,nofail 0 2

Resizing a Volume

Volumes can only be expanded, not shrunk:

Go to Storage > Volumes
Click Resize on the volume
Enter the new size
The PVC expansion happens online, no restart required

After resizing, identify the mounted filesystem again instead of assuming a device letter. For an ext4 filesystem mounted at /mnt/volume:

Bash

sudo resize2fs "$(findmnt -n -o SOURCE --mountpoint /mnt/volume)"

Deleting a Volume

Inside the VPS, unmount the volume first:
Bash
```
umount /mnt/volume
```
Go to Storage > Volumes
Click Delete volume on the volume and confirm

Warning: Deleting a volume permanently deletes the volume and all data on it. Back up the data you need before deleting. Non-destructive detach is not supported.

Technical Details

Storage Backend: Longhorn (replicated block storage)
Storage Class: longhorn-vps-volume
Volume Mode: Block
Access Mode: ReadWriteOnce
Bus: SCSI (for hotplug compatibility)
Filesystem: User's choice (ext4 recommended)
Replication: Configurable via Longhorn (default: 3 replicas)

Questions? Contact support at support@danubedata.ro