This image shows the Boot volume portion of the Create Compute Instance page.

There is text "A boot volume (this is a link) is a detachable device that contains the image used to boot the compute instance."

There are options:

--Specify a custom boot volume size (selected and surroundd by a red border)
The text below the check box reads "Volume performance (this is a link) varies with volume size. Default boot volume size: 75 GB. When you specify a custom boot volume size, service limits apply." 

--Boot volume size (GB) field showing e00.
The text below the field reads "Integer between 50 GB and 32,768 GB (32 TB). Must be larger than the default boot volume size for the selected image."

--Boot volume performance
VPU Balanced
There is text on the right: target volume performance, IOPS: 18000 IPOS, Throughtput: 144 MB/s
There is a slider showing 10.
There is text "Balanced choice for most workloads including those that perform random I/O such as boot disks. Learn more (this is a link). Actaul performance depends on the attached instance's shape. Select the appropriate instance shape to optimize performance. Learn more (this is a link)."

--Use in-transit encryption
The text below the check box reads "Encrypts data (link) in transit between the instance, the boot volume, and the block volumes."

--Encrypt this volume with a key that you manage
The text below the check box reads "By default, Oracle manages the keys that encrypt this volume, but you can choose a key from a vault that you have access to if you want greater control over the key's lifecycle and how it's used. How do I manage my own encryption keys? (this is a link)."