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ceph-osd - ceph object storage daemon


ceph-osd -i osdnum [ --osd-data datapath ] [ --osd-journal
journal ] [ --mkfs ] [ --mkjournal ] [ --mkkey ]


ceph-osd is the object storage daemon for the Ceph distributed file system. It is responsible for storing objects on a local file system and providing access to them over the network.

The datapath argument should be a directory on a btrfs file system where the object data resides. The journal is optional, and is only useful performance-wise when it resides on a different disk than datapath with low latency (ideally, an NVRAM device).


Foreground: do not daemonize after startup (run in foreground). Do not generate a pid file. Useful when run via ceph-run(8).

Debug mode: like -f, but also send all log output to stderr.

Use object store at osddata.

Journal updates to journal.

Create an empty object repository. This also initializes the journal (if one is defined).

Generate a new secret key. This is normally used in combination with --mkfs as it is more convenient than generating a key by hand with ceph-authtool(8).

Create a new journal file to match an existing object repository. This is useful if the journal device or file is wiped out due to a disk or file system failure.

Flush the journal to permanent store. This runs in the foreground so you know when it's completed. This can be useful if you want to resize the journal or need to otherwise destroy it: this guarantees you won't lose data.

Print the cluster fsid (uuid) and exit.

Print the OSD's fsid and exit. The OSD's uuid is generated at --mkfs time and is thus unique to a particular instantiation of this OSD.

Print the journal's uuid. The journal fsid is set to match the OSD fsid at --mkfs time.

Use ceph.conf configuration file instead of the default /etc/ceph/ceph.conf for runtime configuration options.

Connect to specified monitor (instead of looking through ceph.conf).


ceph-osd is part of the Ceph distributed storage system. Please refer to the Ceph documentation at for more information.


ceph(8), ceph-mds(8), ceph-mon(8), ceph-authtool(8)


2010-2014, Inktank Storage, Inc. and contributors. Licensed under Creative Commons BY-SA

January 12, 2014 dev