Pool Management

Overview

Pools are the logical containers for stored data. Each pool has a defined data protection policy (replication or erasure coding), a device class mapping, and a PG count. Creating pools correctly at the outset avoids disruptive reconfiguration later.

Administrator Access Required — This operation requires the admin role. Contact your Xloud administrator if you do not have sufficient permissions.

Prerequisites

Administrator credentials with the admin role
SSH access to a cluster management node
CRUSH map configured with appropriate device class rules (see CRUSH Maps)

Creating Pools

Replicated Pool
Erasure-Coded Pool

Create the pool

Create a replicated pool

ceph osd pool create <POOL_NAME> <PG_COUNT> <PG_COUNT> replicated

For most pools, set PG count to 128 initially — the PG autoscaler will adjust automatically as data volume grows.

Set replication factor

Set replication size (factor)

ceph osd pool set <POOL_NAME> size 3
ceph osd pool set <POOL_NAME> min_size 2

size is the total number of copies. min_size is the minimum needed to serve I/O (allows degraded operation with 2 copies during OSD failure recovery).

Assign a CRUSH rule

Associate the pool with a CRUSH rule that targets the correct device class:

Set CRUSH rule on pool

ceph osd pool set <POOL_NAME> crush_rule replicated_rule_ssd

Use ceph osd crush rule ls to list available rules.

Enable pool application

Tag the pool with its application type so the cluster knows how to manage it:

Enable RBD (block storage) on pool

ceph osd pool application enable <POOL_NAME> rbd

Valid application types: rbd (block), rgw (object), cephfs (file).

Pool appears in ceph osd pool ls detail with correct application and replication settings.

Create an erasure code profile

Create erasure code profile (4+2 on HDD)

ceph osd erasure-code-profile set ec-4-2 \
  k=4 m=2 crush-device-class=hdd

Create erasure code profile (8+3 for large archives)

ceph osd erasure-code-profile set ec-8-3 \
  k=8 m=3 crush-device-class=hdd

Create the pool using the profile

Create erasure-coded pool

ceph osd pool create <POOL_NAME> erasure ec-4-2

Enable pool application

Enable RGW (object storage) on EC pool

ceph osd pool application enable <POOL_NAME> rgw

Erasure-coded pools cannot be used directly for block storage (RBD) without a replicated overlay pool. Use erasure coding primarily for object storage and large object archives.

Pool appears in ceph osd pool ls detail with erasure code profile listed.

Managing Existing Pools

Inspect Pools
Modify Pools
Delete a Pool

List all pools with details

ceph osd pool ls detail

Show pool statistics

ceph df detail

Show specific pool configuration

ceph osd pool get <POOL_NAME> all

Enable PG autoscaling on a pool

ceph osd pool set <POOL_NAME> pg_autoscale_mode on

Set compression on a pool

ceph osd pool set <POOL_NAME> compression_mode aggressive
ceph osd pool set <POOL_NAME> compression_algorithm lz4

Rename a pool

ceph osd pool rename <OLD_NAME> <NEW_NAME>

Pool deletion is irreversible and permanently destroys all data stored in the pool. Confirm with the requesting team that all data has been migrated or is no longer needed before proceeding.

Enable pool deletion (required safety flag)

ceph config set mon mon_allow_pool_delete true

Delete pool (requires double confirmation)

ceph osd pool delete <POOL_NAME> <POOL_NAME> \
  --yes-i-really-really-mean-it

Re-disable pool deletion after use

ceph config set mon mon_allow_pool_delete false

Pool Configuration Reference

Parameter	Command	Notes
Replication size	`ceph osd pool set <pool> size <n>`	Number of copies
Minimum size	`ceph osd pool set <pool> min_size <n>`	Min copies for I/O
CRUSH rule	`ceph osd pool set <pool> crush_rule <rule>`	Device class routing
PG autoscale	`ceph osd pool set <pool> pg_autoscale_mode on`	Automatic PG sizing
Compression	`ceph osd pool set <pool> compression_mode aggressive`	Inline compression
Quotas	`ceph osd pool set-quota <pool> max_bytes <bytes>`	Capacity limit

Next Steps

CRUSH Maps

Configure failure domains and device class rules for pool placement

Storage Tiers

Map pools to Cinder volume types for multi-tier storage

Capacity Planning

Monitor pool utilization and plan expansion

Troubleshooting

Diagnose pool-related issues — PG warnings, capacity alerts

Core Services

Other Services

Pool Management

Overview

Creating Pools

Create the pool

Set replication factor

Assign a CRUSH rule

Enable pool application

Create an erasure code profile

Create the pool using the profile

Enable pool application

Managing Existing Pools

Pool Configuration Reference

Next Steps

CRUSH Maps

Storage Tiers

Capacity Planning

Troubleshooting

​Overview

​Creating Pools

Create the pool

Set replication factor

Assign a CRUSH rule

Enable pool application

Create an erasure code profile

Create the pool using the profile

Enable pool application

​Managing Existing Pools

​Pool Configuration Reference

​Next Steps

CRUSH Maps

Storage Tiers

Capacity Planning

Troubleshooting

Overview

Creating Pools

Managing Existing Pools

Pool Configuration Reference

Next Steps