IBM TotalStorage DS300 Best Practices Manual page 155

Note: Select a global hotspare drive that has the same capacity as the
largest drives installed in the controller. Not all arrays and logical drives will
be protected when drives with a smaller size are defined as hotspare.
When small and large capacity drives are defined as global hotspares, the
largest one is always selected first to rebuild an array with a disabled drive.
array spare add
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Figure 4-96 Spares tab with spare drive
13.Click the Span arrays check box shown in Figure 4-97 to create spanned
arrays. Without checking this checkbox, spanned arrays cannot be created.
Click Next.
Figure 4-97 Checked Span arrays
Chapter 4. TotalStorage DS300 and DS400 management
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