In the most general sense, volumes are data storage devices. Volumes can be either physical or logical. In this manual, the term volume refers to a logical volume with a RAID set, and the terms hard disk drive, disk, and physical volume refer to a physical storage device.
The ReadyDATA treats disks and volumes in the following ways:
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Each logical volume can correspond to one disk.
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A logical volume can be made up of more than one disk.
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You cannot divide a single disk among two or more volumes.
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Although you can install different types of disks within the ReadyDATA, you can select only disks of the same physical performance characteristics to be members of one volume. For example, you cannot mix nearline SATA 7,200 rpm disks with the following disks within one volume:
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SAS 7,200 rpm disks
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SAS 10,000 rpm disks
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SAS 15,000 rpm disks
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SSDs
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After you create a volume you can make the following changes to the volume:
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Expand the volume by adding more disks
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Attach write cache and read cache SSD disks to boost the performance of volumes that contain slower disks such as SATA 7,200 rpm or nearline SAS 7,200 rpm disks
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Export the volume
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Delete the volume
For more information on configuring volumes, see the following support articles:
You can configure any disk that is not allocated to a volume as a hot spare for any volume in case of failure. Because the hot spare provides only a temporary solution, it can be of any physical performance characteristics, that is, it does not need to match the physical performance characteristics of the disks in the volumes. For more information, see the What is a global spare disk and how do I configure it on my ReadyDATA storage system?