IBM ServeRAID User Reference page 75

Figure 26. "Configure controller 1 for clustering" window
18. Select the Shared check boxes for all the logical drives.
19. Do not change the merge-group number from the default provided.
20. Record the controller name, partner name, and merge-group numbers; store
them in a safe place. You will need this information to recover the configuration
if the ServeRAID controller fails.
Note: You can save this information to a file by using the ServeRAID Manager
program:
a. In the ServeRAID Manager tree, click the server.
b. Click Actions → Save printable configuration.
21. Click OK.
22. To exit the ServeRAID Manager program, click File → Exit.
Creating spanned arrays
If you want to assign RAID level-x0 to an array, you must create a spanned array.
For more information about spanned arrays, see Chapter 3, "Understanding RAID
technology" on page 21.
Note: In a failover environment, spanned arrays are supported only by IBM
ServeRAID-4 Ultra160 SCSI controllers.
Complete the following steps to create one or more spanned arrays:
1. If you have not completed steps 1 through 4 in "Configuring ServeRAID arrays
and logical drives" on page 55, do so now.
2. Create identical arrays by doing the following:
a. Click the Array tab in the right panel; then, from the list of ready drives,
select the drives you want to move to the array.
b. Click (Add selected drives) to add the drives to the array.
c. Repeat steps 2a and 2b for each additional array that you want to configure.
Note: To create a spanned array, the arrays to be spanned must be
identical (that is, they must have the same number of physical
drives).
Chapter 6. Configuring two ServeRAID controllers in a failover environment
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