For hard disk drives, which use rotating media, speed is measured in revolutions per minute (RPM). Faster drives provide more input/output operations per second (IOPS) and faster response time.
It is best to use disks of the same speed in an aggregate.
Data ONTAP supports the following rotational speeds for hard disk drives:
Solid-state drives, or SSDs, are flash media-based devices and therefore the concept of rotational speed does not apply to them.
For more information about which disks are supported with specific hardware configurations, see the Hardware Universe at hwu.netapp.com.