---
title: "Adding OSDs\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/ceph/docs/adding-osds?format=md
keywords: index, follow
---

*Submit*

# Adding OSDs

OSDs are added via a new ceph-osd unit. The unit’s underlying machine is understood to house one or more storage devices.

1. Ensure that the cluster is in a healthy state. On any MON (such as the leader unit here) run a status check:

   ```
   juju ssh ceph-mon/leader sudo ceph status
   ```
2. Add a ceph-osd unit:

   ```
   juju add-unit ceph-osd
   ```

A specific underlying machine (MAAS node) can be chosen via [Juju constraints](https://juju.is/docs/juju/manage-machines#heading--manage-machine-constraints).

3. If the new unit’s machine has disks that are not listed by the ceph-osd charm’s osd-devices configuration option then the add-disk action should be used to manually add OSD volumes:

   ```
   juju run --wait ceph-osd/5 add-disk osd-devices=/dev/sde
   ```

Note:

For Juju versions < 3.0, use the `juju run-action` command.

Alternatively, update the value of the osd-devices option:

```
   juju config ceph-osd osd-devices='/dev/sdb /dev/sdc /dev/sde'
```

Note:

An existing OSD cannot be removed from the cluster by mistakenly omitting it from the updated value of option `osd-devices`.

---

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Installing Ceph:
Ceph dashboard](https://ubuntu.com/ceph/docs/install-dashboard)
[Next

Adding MONs](https://ubuntu.com/ceph/docs/adding-mons)

This page was last modified 2 years ago. [Help improve this document in the forum](https://discourse.ubuntu.com/t/adding-osds/18783).