Creating a rank for CKD volumes using the DS CLI

Complete this task to create a rank for a CKD volume. A rank is a logically contiguous storage space that is made up of one or more arrays. You want to assign a rank to every unassigned array.

A rank inherits the characteristics, including RAID type, of its parent array and is given a storage type attribute FB (fixed block) or CKD (count key data). The rank configuration state is unassigned until it is assigned to an extent pool. An unassigned rank is not associated with either rank group 0 or 1. Any unassigned rank can be assigned to an extent pool that is associated with either rank group 0 or 1.

Note: You can assign a rank to an unassigned array and also assign the rank to an extent pool at the same time if you have already created the extent pools and the arrays. Creating extent pools first saves a step in the configuration.

Use the lsarray, mkrank, and lsrank commands to assign a rank to each unassigned array. You must be logged into the DS CLI application and be connected to the storage unit that will be used for open systems host system storage.

To make ranks, perform the following steps:

Issue the lsarray command to ensure you have a list of the unassigned arrays for which ranks must be assigned. Enter the lsarray command at the dscli command prompt with the following parameters and variables:
```
 dscli>lsarray -dev IBM.1750-68FA120 -state unassigned
```
Issue the mkrank command to assign a rank to rank group 0 or 1 according to the rank group number of the assigned extent pool ID. Enter the mkrank command at the dscli command prompt with the following parameters and variables:
```
dscli>mkrank -dev IBM.1750-68FA120 -array A44  
-stgtype ckd -extpool P1
```
Notes:
1. You can specify either the -wait or the -extpool parameter when you use the mkrank command. Either of these parameters allows you to be notified if the rank configuration has failed for any reason.
2. Be aware that when you use the -wait parameter, you cannot issue any other commands until the entire transaction has processed.
Press Enter to create the ranks.
The process of making the rank involves formatting drives. It can take a little time before the process finishes. To check on the process, issue the lsrank command from a different DS CLI session. A successful process generates the following type of message:
```
Sun Aug 11 02:23:49 PST 2004 IBM DS CLI Device: IBM.1750-68FA120  

Rank IBM.1750-75FA120/R44 successfully created.
```
Repeat Step 2 and step 3 until all unassigned arrays are assigned a rank and an extent pool.
Issue the lsrank command to verify that ranks and extent pools have been assigned. Enter the lsrank command at the dscli command prompt with the following parameters and variables:
```
dscli>lsrank -dev IBM.1750-68FA120 -l
```
Press Enter. A report of the rank assignments for your entire storage unit is displayed.