Remove an OSD safely

This runbook covers Remove an OSD safely on a Ceph Tentacle cluster.

When to use

• Active production scenario matching the impact (data-loss-risk)
• The prerequisites are met

Prerequisites

Before starting this runbook, verify each prerequisite has been met. If a prerequisite is not met, resolve it first or escalate.

• The host passes cephadm check-host
• A maintenance window is scheduled
• Replacement capacity or downsize is planned

Pre-checks

Collect evidence before taking action. Evidence is the proof the runbook worked.

# ceph osd tree shows the OSD up + in
# The cluster is HEALTH_OK or HEALTH_WARN with the OSD as the failure source
# smartctl -a /dev/<device> confirms the device is the failing one
# Capacity headroom is at least 25% of used

Procedure

Step 1

ceph osd out <id>

Step 2

Wait for backfill: ceph progress

Step 3

Stop the daemon: ceph orch daemon stop osd.<id>

Step 4

Purge the OSD: ceph osd purge osd.<id> —yes-i-really-mean-it

Step 5

Replace the disk if necessary (Part LVII)

Step 6

Recreate the OSD on the new disk

Verification

After completing the procedure, verify the result:

# ceph osd tree shows the new OSD up + in
# Backfill completes
# CRUSH weight is restored
# Cluster returns to HEALTH_OK

Rollback

If the procedure does not produce the expected verification, roll back:

• If the OSD does not come back: verify the disk and the daemon
• If backfill stalls: tune recovery settings
• If data is at risk: stop the replacement, take a backup

Escalation

If you cannot roll back or the rollback fails, escalate:

• Storage team
• Vendor support for the disk