Overview
Volume extension increases the allocated capacity of an existing block storage volume. The operation grows the underlying block device — the filesystem inside the instance must then be resized separately to use the additional space. Xloud Block Storage supports online extension for volumes that are attached to running instances, depending on the volume type and backend configuration.Prerequisites
- The target volume must exist and have status Available (offline) or In-use (online)
- The new size must be larger than the current size — volumes cannot be shrunk
- For online extension, the instance must be running and the guest OS must support online resize
Online vs Offline Extension
| Mode | Volume Status | Instance Required | Filesystem Resize | Downtime |
|---|---|---|---|---|
| Online | In-use (attached) | Running | Live, no reboot needed | None |
| Offline | Available (detached) | Not required | After re-attach | Brief detach window |
Online extension is supported for most Linux filesystems (ext4, XFS) on volumes backed
by distributed storage. The block device grows automatically — the filesystem does not
resize automatically and must be expanded inside the instance after the volume is extended.
Extend a Volume
- Dashboard
- CLI
Locate the volume
Log in to the Xloud Dashboard (
https://connect.<your-domain>) and navigate to
Project → Volumes → Volumes.Extend the volume
Click Actions → Extend Volume on the target volume. Enter the new total size
in GiB — the value must be larger than the current size.Click Extend Volume to confirm.
Resize the Filesystem
After extending the block device, resize the filesystem inside the instance to use the additional capacity. The correct command depends on the filesystem type.- ext4
- XFS
- LVM (logical volume)
ext4 filesystems can be resized online while mounted:
Resize ext4 filesystem (online)
Verify new capacity
Filesystem expanded to the full volume size with no downtime.
Troubleshooting
Extension fails with 'Invalid volume: Volume status must be available or in-use'
Extension fails with 'Invalid volume: Volume status must be available or in-use'
Cause: The volume is in an intermediate state (Wait for the operation to complete or contact your administrator if the volume is
stuck in an error state.
creating, deleting, error,
or migrating) that does not permit size changes.Resolution:Check volume status
Filesystem does not show new capacity after extension
Filesystem does not show new capacity after extension
Cause: The block device was extended but the filesystem was not resized.Resolution: Run the appropriate filesystem resize command (
resize2fs for ext4,
xfs_growfs for XFS) as described in the Resize the Filesystem section above.
Verify with df -h that the new capacity is visible.resize2fs reports 'No space left on device'
resize2fs reports 'No space left on device'
Cause: The filesystem resize is being attempted on a device that has not yet
been extended at the block level, or the extension has not propagated to the guest.Resolution:Compare the reported bytes against the expected new size. If the block device still
shows the old size, wait a few seconds and retry — the backend may still be
completing the resize operation.
Check block device size inside instance
Next Steps
Volume Snapshots
Create a snapshot before extending to preserve a recovery point
Attach / Detach
Connect volumes to compute instances and prepare filesystems
Volume Backups
Back up volume data to a separate target for long-term retention
Create a Volume
Provision a new volume with the correct initial capacity and storage tier