> # About DPVM Databases

> The DPVM database consists of a series of device mapping entries. Each entry consists of a device pWWN or nWWN assignment along with the dynamic VSAN to be assigned. You can configure a maximum of 16,000 DPVM entries in the DPVM database. This database is global to the whole switch (and fabric) and is not maintained for each VSAN.

> The DPVM feature uses three databases to accept and implement configurations.

> - Configuration (config) database—All configuration changes are stored in the configuration database when distribution is disabled.
> - Active database—The database currently enforced by the fabric.
> - Pending database—All configuration changes are stored in the DPVM pending database when distribution is enabled (see the "About DPVM Database Distribution" topic).

> Changes to the DPVM config database are not reflected in the active DPVM database until you activate the DPVM config database. Changes to the DPVM pending database are not reflected in the config or active DPVM database until you commit the DPVM pending database. This database structure allows you to create multiple entries, review changes, and let the DPVM config and pending databases take effect.

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