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The Data Management API (DMAPI)

The Data Management API (DMAPI) is the mechanism within the XFS filesystem for passing file management requests between the kernel and a hierarchical storage management system (HSM).

In order to configure an HSM, you must ensure that you have installed DMAPI and the appropriate patches.

This page provides information on the following topics:

  • DMAPI status in XFS
  • Building DMAPI
  • The DMAPI device
  • The DMAPI libraries
  • Mounting filesystems for use with DMAPI
  • DMAPI Status in XFS

    The current status of the individual DMAPI functions in XFS can be found in the file linux/fs/xfs/dmapi/Status.

    Building DMAPI

    To build DMAPI, set the DMAPI config flag when you configure XFS as part of your build. This flag is in the collection of XFS configuration options.

    The DMAPI Device

    In order to use DMAPI, you need to create the device /dev/dmapi; this is the interface the user library uses to communicate with the kernel side of DMAPI.

    Execute the following command to create the DMAPI device:

    The DMAPI Libraries

    The user library for DMAPI is cmd/xfs/libdm/libdm.so. The user library requires the handle library cmd/xfs/handle/libhandle.a. The tests in cmd/xfs/libdm link with these libraries.

    Mounting Filesystems for use with DMAPI

    In order for filesystems to be managed by an HSF, they must be mounted to enable the DMAPI interface. To mount a filesystem for use with DMAPI, use the following command:



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