1.2.10 Templates

During file creation, every file in Exascale is associated with attributes that govern how the file is stored and managed.

An Exascale template is a named collection of file storage attribute settings. For example:

name: DATAFILE
mediaType: HC
redundancy: high
contentType: DATA

With templates, you can set file storage attributes automatically and consistently. When creating a file, Exascale automatically uses the template that matches the file type by default. For example, when Oracle Database creates a data file, the DATAFILE template is automatically used by default.

Note that templates only govern the assignment of file storage attributes during file creation. You cannot change the file storage attributes after the file is created. Any change to a template applies only to files created after the change.

Within Exascale, templates are defined at two levels:

• Cluster Templates are defined at the cluster level.

  A cluster template contains settings for the file storage attributes: mediaType, redundancy, and contentType.

  A cluster template is used if no vault-level template exists to override it.

• Vault Templates are defined at the vault level.

  A vault template may also contain settings for the file storage attributes: mediaType, redundancy, and contentType.

  Additionally, starting with Oracle Exadata System Software release 26.1.0, a vault template can also include a storagePool setting to specify the name of a storage pool used to store files created with the template. If a template specifies both mediaType and storagePool, the values must be compatible. For example, you cannot specify the use of high capacity (HC) storage media (mediaType=HC) and also specify the name of a storage pool that uses extreme flash (EF) storage.

  A vault template defines vault-specific attributes that override the corresponding cluster template. For example, your cluster-level DATAFILE template may specify using HC storage media (mediaType=HC), but you may override that setting for a vault by having a vault-level DATAFILE template that specifies EF storage (mediaType=EF). Or, starting with Oracle Exadata System Software release 26.1.0, you could define a vault-level DATAFILE template that uses a specific storage pool rather than nominating a media type.

Additionally, User Templates are templates with user-specified names that do not correspond to a specific file type. User templates effectively override file-type templates. However, to use a user template, you must explicitly specify it during file creation. User templates can be defined at the cluster level or at the vault level. A vault-level user template will override a cluster-level user template having the same name.

Starting with Oracle Exadata System Software release 26.1.0, an Exascale cluster can support multiple storage pools for each media type. If a template does not specify a storagePool setting and multiple storage pools match the template's mediaType setting, Exascale automatically selects the storage pool to use.