osdmaptool mapfilename [--print] [--createsimple numosd
[--pgbits bitsperosd ] ] [--clobber]


osdmaptool is a utility that lets you create, view, and manipulate OSD cluster maps from the Ceph distributed storage system. Notably, it lets you extract the embedded CRUSH map or import a new CRUSH map.



will simply make the tool print a plaintext dump of the map, after any modifications are made.


will allow osdmaptool to overwrite mapfilename if changes are made.

--import-crush mapfile

will load the CRUSH map from mapfile and embed it in the OSD map.

--export-crush mapfile

will extract the CRUSH map from the OSD map and write it to mapfile.

--createsimple numosd [--pgbits bitsperosd]

will create a relatively generic OSD map with the numosd devices. If --pgbits is specified, the initial placement group counts will be set with bitsperosd bits per OSD. That is, the pg_num map attribute will be set to numosd shifted by bitsperosd.


To create a simple map with 16 devices:

osdmaptool --createsimple 16 osdmap --clobber

To view the result:

osdmaptool --print osdmap


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

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