Key Concepts
Physical Disk
A storage device (HDD, SSD, or NVMe) attached to a cluster node that can potentially be used as an OSD.
Available
A disk that meets all requirements and can be used to create a new OSD.
In Use
A disk that already has one or more OSDs deployed on it.
Rejected
A disk that cannot be used due to specific reasons (partitions, filesystem, size, etc.).
Required Permissions
| Action | Permission |
|---|---|
| View Physical Disks | iam:project:infrastructure:ceph:read |
This page is read-only. To create OSDs from available disks, use the OSDs page.
Disk Status
| Status | Description |
|---|---|
| Available | Disk is clean and can be used for OSD creation |
| In Use (OSD) | Disk has one or more OSDs deployed (shows OSD IDs) |
| Rejected | Disk cannot be used; hover to see rejection reasons |
| Unused | Disk is not available but has no OSDs or rejection reasons |
Disk Types
| Type | Icon | Description |
|---|---|---|
| HDD | Hard Drive | Traditional rotational hard disk drive |
| SSD | Disc | Solid-state drive |
| NVMe | Disc | High-performance NVMe solid-state drive |
How to View Physical Disks
Select Cluster
Choose a Ceph cluster from the cluster dropdown. Only ready (bootstrapped) clusters show disk inventory.
View Statistics
Review the summary cards showing:
- Total Disks: All physical disks across cluster nodes
- Available: Disks ready for OSD creation
- In Use (OSD): Disks with active OSDs
- Rejected: Disks that cannot be used
- HDD: Count of rotational drives
- SSD/NVMe: Count of solid-state drives
Filter and Search
Use filters to focus on specific disk states:
- Available: Show only disks ready for use
- In Use (OSD): Show only disks with OSDs
- Rejected: Show only unusable disks
Disk Table Fields
| Field | Description |
|---|---|
| Device | Device path (e.g., /dev/sda) and device ID |
| Host | Node where the disk is located |
| Type | Disk type: HDD, SSD, or NVMe |
| Size | Total disk capacity |
| Model | Disk model name and vendor |
| Status | Current status with details |
Understanding Disk Status
Available Disks
Available disks meet all requirements for OSD creation:- No existing partitions or filesystems
- Sufficient size (typically > 5GB)
- Not mounted or in use
- Properly detected by the system
In Use (OSD) Disks
Disks with OSD status show which OSD IDs are using them:- Single OSD per disk is typical
- Multiple OSDs may exist on large disks (with partitioning)
- The OSD ID links the disk to the OSD configuration
Rejected Disks
Rejected disks have one or more reasons preventing OSD creation. Common rejection reasons include:| Reason | Description |
|---|---|
| Has partitions | Disk has existing partition table |
| Has filesystem | Disk has a filesystem (ext4, xfs, etc.) |
| Too small | Disk is below minimum size requirement |
| Locked | Disk is locked by another process |
| Has holders | Other devices depend on this disk (dm, raid) |
| Mounted | Disk or partition is currently mounted |
To make a rejected disk available, you must resolve the rejection reasons. This typically involves removing partitions, filesystems, or unmounting the disk.
Statistics Cards
Total Disks
The total count of all physical disks detected across all cluster nodes.Available
Disks that are clean and ready for OSD creation. These appear in the Add OSD list on the OSDs page.In Use (OSD)
Disks that already have Ceph OSDs deployed. Each disk shows its associated OSD ID(s).Rejected
Disks that cannot be used for OSD creation due to existing data, partitions, or other restrictions.HDD
Count of rotational (spinning) hard disk drives. HDDs are identified by therotational property.
SSD/NVMe
Count of solid-state drives including both SATA SSDs and NVMe drives. These offer faster I/O than HDDs.Troubleshooting
No disks showing in the inventory
No disks showing in the inventory
- Verify the cluster is bootstrapped and ready
- Check that nodes have the OSD role assigned
- Ensure disks are properly connected and detected by the OS
- Try refreshing the inventory
Disk shows as rejected
Disk shows as rejected
- Hover over the Rejected badge to see specific reasons
- Common causes: existing partitions, filesystems, or mounts
- Use
lsblkon the node to inspect the disk - Clean the disk with
wipefsorddif appropriate
Available disk not appearing in Add OSD
Available disk not appearing in Add OSD
- Refresh both the Physical Disks and OSDs pages
- Verify the disk shows as Available (not just Unused)
- Check that the host has the OSD role in the cluster
- Ensure no other process is using the disk
Disk shows wrong type (HDD vs SSD)
Disk shows wrong type (HDD vs SSD)
- Disk type is detected from system properties
- Virtual disks may not report type correctly
- Check
/sys/block/<device>/queue/rotationalon the node - Type detection depends on disk firmware reporting
Disk size shows as 0 or incorrect
Disk size shows as 0 or incorrect
- Disk may not be properly initialized
- Check disk health with
smartctl - Verify disk is detected in
lsblkoutput - Some virtual disks report size differently
Disk missing from inventory after adding OSD
Disk missing from inventory after adding OSD
- After OSD creation, the disk status changes to “In Use”
- Refresh the page to see updated status
- The disk will show the OSD ID in its status
FAQ
What makes a disk 'available'?
What makes a disk 'available'?
A disk is available when it:
- Has no partition table
- Has no filesystem
- Is not mounted
- Meets minimum size requirements
- Is not used by LVM, RAID, or other device mappers
- Is not locked by another process
How do I make a rejected disk available?
How do I make a rejected disk available?
To prepare a rejected disk:
- Identify the rejection reason by hovering over the status
- Unmount any mounted partitions
- Remove partitions with
fdiskorparted - Wipe filesystem signatures with
wipefs -a /dev/sdX - Refresh the inventory to see updated status
Can I use a disk that has existing data?
Can I use a disk that has existing data?
No. Ceph requires clean disks for OSD creation. You must remove all data, partitions, and filesystems before using a disk. This ensures data integrity and allows Ceph to manage the entire disk.
Why do some disks show as 'Unused' instead of 'Available'?
Why do some disks show as 'Unused' instead of 'Available'?
Unused status means the disk:
- Is not available for OSD creation
- Does not have an OSD deployed
- Has no specific rejection reasons
How is disk type (HDD/SSD/NVMe) determined?
How is disk type (HDD/SSD/NVMe) determined?
Disk type is detected from:
- The
rotationalflag in/sys/block/<device>/queue/rotational - Device naming patterns (nvme* for NVMe)
- SMART data and device identification
Can multiple OSDs use the same physical disk?
Can multiple OSDs use the same physical disk?
While technically possible through partitioning, it’s not recommended:
- Modern best practice is one OSD per physical disk
- Multiple OSDs per disk was common with older small disks
- Single OSD per disk provides better failure isolation
- Ceph orchestrator typically creates one OSD per disk
What is the minimum disk size for an OSD?
What is the minimum disk size for an OSD?
The minimum depends on your Ceph version and configuration:
- Default minimum is typically 5GB
- Production systems should use much larger disks
- Very small disks are often rejected automatically
- Check your Ceph configuration for specific limits
Why doesn't the inventory show all disks on a node?
Why doesn't the inventory show all disks on a node?
Some disks may be excluded:
- System/boot disks are typically filtered out
- Disks without proper block device entries
- Removable media may be excluded
- Disks in certain device mapper configurations
lsblk on the node to see all block devices.How often is the disk inventory updated?
How often is the disk inventory updated?
The inventory is fetched from the Ceph Dashboard API when you:
- Load or refresh the Physical Disks page
- Add or remove OSDs
- The underlying Ceph inventory updates periodically