About Aggregates

Aggregates are containers that capture all the physical aspects of storage: disks, RAID groups, and plexes. Aggregates serve as containers for both traditional and flexible volumes (or FlexVol volumes), but the relationship of the aggregate to each kind of volume is very different.

• When an aggregate contains a traditional volume, the two entities are bound so tightly together that the boundaries between the two become transparent, and they are both identified by a single name.

From a management perspective, this means that the logical properties of the traditional volume are commingled with the physical properties defined in its containing aggregate. For example, if you add a disk to an aggregate containing a traditional volume, that action increases the size of the user-visible file system portion of the traditional volume as well.

• An aggregate is much more loosely bound to a flexible volume, so that each is identified by a separate name and managed independently of the other. For example, you can increase or decrease the logical size of a flexible volume independently of its containing aggregate or of other flexible volumes contained in the same aggregate. In order to realize any changes to the physical storage on which a flexible volume resides, you need to directly modify its containing aggregate. Any such physical change to an aggregate affects all the flexible volumes it contains. For example, adding a disk to an aggregate increases the pool of free blocks available to all of its contained flexible volumes.

An aggregate can contain one or more flexible volumes or a single traditional volume. You cannot mix volume types on an aggregate.

Note: For backward compatibility, volumes created prior to Data ONTAP 7.0 are displayed as traditional volumes in FilerView.

For more information on aggregates, see the Data ONTAP Storage Management Guide.