Skip to main content
RunBook Academy

← All break/fix scenarios in Ceph

advancedceph-backup~22 min

Backup exists but restore procedure fails - format mismatch

Reported symptoms

  • ●The backup file is the right size
  • ●rbd import <file> <pool>/<image> fails
  • ●The backup was created with a different format / features

Evidence

  • · rbd info <backup> reports the format
  • · file <backup> reports the file type
  • · The destination pool has incompatible defaults
Diagnosis and resolutionclick to reveal

Root cause

The backup file was created with an older format or feature set. The destination pool expects the new format.

Remediation

Verify the format; use the correct import flags; if needed, convert the backup file (qemu-img convert); retry the import.

Verification

The image is created in the pool; rbd info reports the new image; data is readable.

Prevention

Document the backup format and features; rehearse restore; maintain format consistency.

Architecture

The student examines the broken architecture diagram and identifies the responsible component. The cluster is running Ceph Tentacle (20.2.x); the incident is one a production operator must diagnose from the evidence presented.

Symptoms

  • The backup file is the right size
  • rbd import <file> &lt;pool&gt;/<image> fails
  • The backup was created with a different format / features

Evidence

  • rbd info <backup> reports the format
  • file <backup> reports the file type
  • The destination pool has incompatible defaults

Student investigation

The student follows the methodology: define the symptom, determine the impact, gather evidence, identify the component, form a hypothesis, test safely, restore, validate.

Progressive hints

  • Hint 1: check the cluster state with ceph -s first.
  • Hint 2: read ceph health detail and identify the affected PGs / OSDs / daemons.
  • Hint 3: use ceph osd tree, ceph pg dump, or ceph mds stat as the next-level diagnostic.
  • Hint 4: the root cause is documented in the frontmatter root_cause field.

Validation

The student runs the verification steps and confirms the symptom cleared.

Root cause

See the frontmatter root_cause field.

Remediation

Apply the fix from the frontmatter remediation field.

Prevention

Apply the prevention measures from the frontmatter prevention field.