Creating LUN volumes for System i systems

Complete this task to create fixed block LUN volumes for System i systems.

You must have completed the following tasks before you can create your fixed block LUN volumes:

Created your extent pools
Created your arrays
Created and assigned your ranks

When you begin your initial configuration, the LSSs and address groups do not exist. The LSS's are created when the first volume of the LSS's is defined during the processing of the mkfbvol command; likewise, the address group gets defined when the first LSS is defined.

When you create volumes, you must designate the logical subsystem (LSS) that a particular volume belongs to. After you assign a volume ID, use the first two digits to designate the LSS. For example, if you specify a volume ID of 1900, the volume then belongs to LSS 19.

Consider the following specifications before you create your fixed block LUN volumes:

Volumes that belong to an even numbered rank group (cluster) must be in an even numbered LSS; volumes that belong to an odd numbered rank group (cluster) must be in an odd numbered LSS. The cluster that a volume belongs to is determined by specifying the extent pool that the volume is assigned to.
LSS number 1F is reserved for internal use and must not be used as a volume ID.
You must define each volume as protected or unprotected. This is simply a notification to i5/OS; it does not mean that the volume is protected or unprotected. In reality, all LUNs are protected, either by RAID5 or RAID10. Defining a volume as unprotected means that it is available for i5/OS to mirror that volume to another internal or external volume of equal capacity. Unless you intend to use i5/OS (host based) mirroring, define your logical volumes as protected.
Under some circumstances, you might want to mirror the i5/OS internal Load Source Unit (LSU) to a LUN in the DS6000. In this case, define only one LUN volume as unprotected; otherwise, i5/OS attempts to mirror all unprotected volumes.
In general, it is best to use one LSS for volumes from one rank.

Perform the following steps to create fixed block LUN volumes:

View your list of fixed block extent pool IDs and determine which extent pool IDs that you want to use as the source for the fixed block logical volumes. You obtained this list when you first created your extent pools. If this list is not available, issue the lsextpool command to obtain the list of extent pool IDs. Enter the lsextpool command at the dscli command prompt with the following parameters and variables:
```
dscli>lsextpool -dev IBM.1750-13AAD7A -stgtype fb -l
```
Extent pool attributes determine the size and quantity of volumes that can be created. The extent pool ID (even | odd) indicates the storage server (0 | 1), which dictates that the LSS ID component of the volume ID must be an even or an odd number.
Issue the mkfbvol command to create fixed block LUN volumes for the specified LSS. Enter the mkfbvol command at the dscli command prompt with the following parameters and variables:
```
dscli>mkfbvol -dev IBM.1750-13AAD7A -extpool p0
 -os400 A05 -name i5_unprot_#h 1001-1002 
```
Consider the following conditions with regard to the command example in this step:
- The -extpool parameter identifies a fixed block extent pool containing available data extents.
- The -os400 parameter allows you to designate the size and protection of a LUN volume by specifying the volume model. The example shows LUN volumes of protected model type A05 with a size of 35.1 decimal gigabytes.
- The -name parameter allows you to assign an easy-to-use label or nickname to the volume. The volume name parameter can include a wildcard (#d or #h) that inserts a decimal or hexadecimal volume ID value into the volume name.
  Note: The hexadecimal designation does not apply to the volume ID number or the number of volumes that were created by the command. It only applies to the unique name that you have assigned. Also, when you process this command, the volume name that you have assigned does not appear in the confirmation message. To view the volume name that you have assigned, issue the lsfbvol or showfbvol command.
- The example provides a range of numbers (0101 - 0102) for the number of volumes to be created. The actual number of volumes that can be created is 255 per LSS based on the following criteria:
  - The volume ID is a 32 bit number that can be represented as 4 hexadecimal digits in the form of XYZZ where X is the address group (0 - 1), XY together is the logical subsystem number 00 - 1E, and ZZ is the volume number (00 - FF).
  - You can define up to 31 LSSs in a storage unit. Even numbered LSSs have an association with storage unit server 0. Odd numbered LSSs have an association with storage unit server 1. LSS number 1F is reserved.
Repeat step 2 for all of the required logical volumes for each LSS.
Issue the lsfbvol command to display a report you can use to confirm the status of your LUN volumes. Enter the lsfbvol command at the dscli command prompt with the following parameters and variables:
```
dscli>lsfbvol -dev IBM.1750-13AAD7A -l 
```