Add an OSD to an existing host

This runbook covers Add an OSD to an existing host on a Ceph Tentacle cluster.

When to use

• Active production scenario matching the impact (service-affecting)
• 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.

• A new disk is installed
• The disk is at least as large as the smallest existing OSD
• The cluster has enough headroom for backfill

Pre-checks

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

# ceph -s is HEALTH_OK
# ceph osd tree shows the target host
# ceph orch device ls --hostname=<host> shows the new disk
# Time and DNS are healthy

Procedure

Step 1

ceph orch daemon add osd <host>:<device>

Step 2

OR ceph-volume lvm create —data <device> —bluestore

Step 3

Verify the new OSD comes up: ceph osd tree

Step 4

Wait for backfill: ceph progress

Step 5

Verify the PG distribution is healthy: ceph osd df tree

Verification

After completing the procedure, verify the result:

# ceph osd tree shows the new OSD up + in
# Backfill completes
# PGs return to active+clean
# ceph df shows the new usable capacity

Rollback

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

• If the OSD fails to create: verify the device is healthy
• If backfill is slow: tune recovery settings
• If the OSD comes up briefly then crashes: device failure suspected

Escalation

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

• Storage team
• Hardware vendor if the disk fails immediately