Notice

This document is for a development version of Ceph.

Local Pool Module

The localpool module can automatically create RADOS pools that are localized to a subset of the overall cluster. For example, by default, it will create a pool for each distinct rack in the cluster. This can be useful for deployments where it is desirable to distribute some data locally and other data globally across the cluster. One use-case is measuring performance and testing behavior of specific drive, NIC, or chassis models in isolation.

Enabling

The localpool module is enabled with:

ceph mgr module enable localpool

Configuring

The localpool module understands the following options:

subtree

which CRUSH subtree type the module should create a pool for.

type

str

default

rack

failure_domain

what failure domain we should separate data replicas across.

type

str

default

host

pg_num

default pg_num for any created local pool

type

int

default

128

num_rep

default replica count for any created local pool

type

int

default

3

min_size

value to set min_size to (unchanged from Ceph’s default if this option is not set)

type

int

prefix

name prefix for any created local pool

type

str

default

by-$subtreetype-

These options are set via the config-key interface. For example, to change the replication level to 2x with only 64 PGs,

ceph config set mgr mgr/localpool/num_rep 2
ceph config set mgr mgr/localpool/pg_num 64

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