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Capacity for volumes

The drives in your storage array provide the physical storage capacity for your data. Before you can begin storing data, you must configure the allocated capacity into logical components known as pools or volume groups. You use these storage objects to configure, store, maintain, and preserve data on your storage array.

Using capacity to create and expand volumes​

You can create volumes from either the unassigned capacity or free capacity in a pool or volume group.

  • When you create a volume from unassigned capacity, you can create a pool or volume group and the volume at the same time.
  • When you create a volume from free capacity, you are creating an additional volume on an already existing pool or volume group.
Note
The DE Plugin for vCenter interface does not provide an option to create thin volumes.

Reported capacity for volumes​

The reported capacity of the volume is equal to the amount of physical storage capacity allocated. The entire amount of physical storage capacity must be present. The physically allocated space is equal to the space that is reported to the host.

You normally set the volume's reported capacity to be the maximum capacity to which you think the volume will grow. Volumes provide high and predictable performance for your applications mainly because all of the user capacity is reserved and allocated upon creation.

Capacity limits​

The minimum capacity for a volume is 1 MiB, and the maximum capacity is determined by the number and capacity of the drives in the pool or volume group.

When increasing reported capacity for a volume, keep the following guidelines in mind:

  • You can specify up to three decimal places (for example, 65.375 GiB).
  • Capacity needs to be less than (or equal to) the maximum available in the volume group.

    When you create a volume, some additional capacity is pre-allocated for Dynamic Segment Size (DSS) migration. DSS migration is a feature of the software that allows you to change the segment size of a volume.

  • Volumes larger than 2 TiB are supported by some host operating systems (maximum reported capacity is determined by the host operating system). In fact, some host operating systems support up to 128 TiB volumes. Refer to your host operating system documentation for additional details.