With the introduction of Exascale, storage is physically organized in Exascale storage pools, each containing numerous pool disks.
An Exascale vault is a logical storage container that uses the physical resources provided by Exascale storage pools. By default, a vault can use all the associated storage pool resources. However, an Exascale administrator can limit the amount of space, I/O resources (I/Os per second, or IOPS), and cache resources associated with each vault.
To an end-user and Oracle Database, a vault appears like a top-level directory that contains files. Referencing files on Exascale is essentially the same as using an ASM disk group, except that Exascale uses the convention of beginning vault names with the ampersand (@) character (for example, @VAULT1) instead of the plus (+) character (for example, +DATA).
However, Exascale vaults are much more sophisticated than ASM disk groups.
Exascale vaults facilitate strict data separation, ensuring that data is isolated to specific users and separated from other data and users. A vault, and its contents, are inaccessible to users without the appropriate privileges. For example, without the correct entitlements, users of one vault cannot see another vault, even though data from both vaults is striped across the same underlying storage pool (as illustrated in the diagram).
Furthermore, Exascale inherently distinguishes between various file types and automatically places data files and associated recovery files on separate pool disks. This enables users and databases to maintain all files within one vault instead of different disk groups for data and recovery files.
On systems that also use Oracle ASM, you can continue to define and use ASM disk groups, which reside alongside the Exascale storage pools.