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DMAPI

DMAPI

Posted Aug 13, 2010 23:48 UTC (Fri) by giraffedata (subscriber, #1954)
Parent article: The 2010 Linux Storage and Filesystem Summit, day 2

There was a brief discussion about the DMAPI specification, which describes an API to be used to control hierarchical storage managers.

DMAPI isn't an API; it's a class of APIs -- ones that contain certain broad data management functions you need for a hierarchical storage manager. For example, "we're designing a simple DMAPI that has only 3 functions." The API almost everyone calls "DMAPI" is really called XDSF.

It's sort of like IDE is usually used as a misnomer for ATA.


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DMAPI

Posted Aug 17, 2010 4:24 UTC (Tue) by jone (guest, #62596) [Link]

erm .. i think you mean XDSM which is a specification for Data Management (DM) applications which also specified an API (XDSF is the security framework) .. but, you're right - DMAPI was really the interface to the specification that defines multiple APIs to deal with DM .. IBM and SGI really latched onto this since it meant that they didn't have to rewrite their global filesystems (GPFS, [C]XFS) to deal with EAs, offline/partials/etc, region mgmt and auth, etc ..

the big problem with DMAPI is that it simply doesn't scale .. take a look at the NERSC/LBNL paper for some hints at some of the architectural issues .. metadata scan performance is ultimately key, and the ability to abstract this away when necessary can be quite valuable

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