IBM System x3750 M4 Type 8722 Installation And Service Manual page 68

4. When you install a combination of 2.5-inch and 1.8-inch drive backplanes in the
In the following illustration, the drive bay IDs are in sequential order because all
of the drive backplanes are 2.5-inch drive backplanes.
In the following illustration, you have a combination of drive backplanes. This
example shows a 2.5-inch drive backplane and a 1.8-inch drive backplane installed
in the server. In this instance, the drive bay IDs will require a gap in the bay ID
numbering between the drive IDs in the 2.5-inch and 1.8-inch drive backplanes.
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System x3750 M4 Types 8722 and 8733: Installation and Service Guide
same server, the drive bay ID numbering is reset by skipping bay ID numbers
based on the number of 2.5-inch drive backplanes that are installed to the left
of the 1.8-inch drives backplanes.
For example, if the server has a 4x2.5-inch drive backplane and a 8x1.8-inch
backplane configuration, the drive bay IDs of the four drives in the 4x2.5-inch
drive backplane are 0 through 3. The drive bay IDs of the eight drives in the
8x1.8-inch drive backplane starts with an ID of 8 through 15. Since the drive
bay IDs of the drives in the 4x2.5-inch backplane are 0 through 3, the IDs reset
and skip four ID numbers (because the first backplane supports four drives),
then the drive IDs in the 8x1.8-inch drive backplane starts with an ID of 8
through 15.
If a 8x2.5inch drive backplane had been installed, instead of the 4x2.5-inch
drive backplane, the IDs are reset and skip eight ID numbers, then the drive
IDs of the drives in the 8x1.8-inch drive backplane would start at 16 through
23. See the following example illustrations and the illustrations in "Supported
SAS/SATA drive backplane configurations" on page 53 for more information.
8 9 10
0 1 2 3
11 12 13 14 15
Empty Empty