Create A Mirrorset; Initialize The Mirrorset; Add The Mirrorset As A Logical Unit - StorageWorks RAID Array 410 Installation Manual

2.10

Create a MIRRORset

If you require MIRRORsets to be available to the host as Logical Units, you must now
combine disks into a MIRRORset. MIRRORsets must have at least two members, and can
have as many as six. This example creates a two member MIRRORset using the ADD
MIRRORSET command.
SWXRC> ADD MIRRORSET MIRROR_SET_1 DISK120 DISK220
In this example, "MIRROR_SET_1" is the name of the MIRRORset, and it is followed by a
list of the disks to be included in the MIRRORset. The names of the MIRROR sets are user
selectable. Performance of your MIRROR sets will be optimized if each MIRRORset
includes disks from different channels as shown in the example.

2.10.1 Initialize the MIRRORset

Before you can put the MIRRORset into service, it must be initialized.
SWXRC> INITIALIZE MIRROR_SET_1

2.10.2 Add the MIRRORset as a Logical Unit

To make a MIRRORset available to the host computer, you must identify it as a host logical
unit. The unit number is a one or three digit number preceded by "D". The unit number
identifies the controller's target number and the MIRRORset as the Logical Unit (LUN)
connected to the target. Units identified with controller target number 0 have a single digit
number which corresponds to LUN number. For example, D5 would be target 0, LUN 5.
Units identified with controller targets 1, 2 and 3 use a 3 digit number. The first digit
corresponds to the controller target number, the second digit is always 0 and the third digit to
the LUN number. For example, D400 would be target 4, LUN 0. You must now identify the
STRIPEsets as Host Logical Units by using the ADD UNIT command.
SWXRC> ADD UNIT D400 MIRROR_SET_1
This example uses the controller target of 4 and LUN 0.
The final step in creating the MIRRORset is to enable the writeback cache. A single CLI
command enables that feature for the entire MIRRORset:
SWXRC> SET D400 WRITEBACK_CACHE
Where: D400 represents the host logical unit of the MIRRORset described above.
EK–SMRA3–IG. C01
For some operating systems Logical Units must be sequential.
They must begin with D0 and be followed by D1, D2, D3, ..... etc.
Chapter 2. Creating an Initial Configuration
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