Logical units and target ports on IBM XIV Storage System models
On IBM® XIV® Storage System, logical units (LUs) are enumerated devices that have the same characteristics as LUNs.
LUNs
An IBM XIV Storage System Logical Unit is referred to as a volume. IBM XIV Storage System and volumes are enumerated devices that all share identical characteristics.
A single IBM XIV Storage System volume can potentially consume the entire capacity that is allocated for Storwize® V3700 storage pools, and it can also exceed the Storwize V3700 1 PB LUN size limit. Any LUN that is 1 PB or larger is truncated to 1 PB, and a warning message is generated for each path to the LUN.
IBM XIV Storage System volumes consume chunks of 17,179,869,184 bytes (17 GB), although you can create volumes with an arbitrary block count.
LUN IDs
LUNs that are exported by IBM XIV Storage System models report Identification Descriptors 0, 1, and 2 in VPD page 0x83. Storwize V3700 uses the EUI-64 compliant type 2 descriptor CCCCCCMMMMMMLLLL, where CCCCCC is the IEEE company ID, MMMMMM is the System Serial Number that is transcribed to hexadecimal (10142->0x010142, for example) and LLLL is 0000-0xFFFF, which increments each time a LUN is created. You can identify the LLLL value by using the IBM XIV Storage System GUI or CLI to display the volume serial number.
LUN creation and deletion
IBM XIV Storage System LUNs are created and deleted by using the IBM XIV Storage System GUI or CLI. LUNs are formatted to all zeros upon creation, but to avoid a significant formatting delay, zeros are not written.
Special LUNs
IBM XIV Storage System systems do not use a special LUN; storage can be presented by using any valid LUN, including 0.
LU access model
IBM XIV Storage System systems have no specific ownership of any LUN by any module. Because data is striped over all disks in the system, performance is generally unaffected by the choice of a target port.
LU grouping
IBM XIV Storage System models do not use LU grouping; all LUNs are independent entities. To protect a single IBM XIV Storage System volume from accidental deletion, you can create a consistency group that contains all LUNs that are mapped to a single Storwize V3700 clustered system.
LU preferred access port
IBM XIV Storage System models have no preferred access ports.
Detecting ownership
Ownership is not relevant to IBM XIV Storage System models.
LUN presentation on XIV Nextra systems
- LUNs can be presented to one or more selected hosts.
- XIV Nextra maps consist of sets of LUN pairs and linked hosts.
- A volume can appear only once in a map.
- A LUN can appear only once in a map.
- A host can be linked to only one map.
- Create a map with all of the volumes that you intend to manage with the Storwize V3700 system.
- Link the WWPN for all node ports in the Storwize V3700 system into the map. Each Storwize V3700 node port WWPN is recognized as a separate host by XIV Nextra systems.
LUN presentation on IBM XIV Type Number 2810 systems
- LUNs can be presented to one or more selected hosts or clusters.
- Clusters are collections of hosts.
- Use the IBM XIV Storage System GUI to create an IBM XIV Storage System cluster for the Storwize V3700 system.
- Create a host for each node in the Storwize V3700.
- Add a port to each host that you created in step 2. You must add a port for each port on the corresponding node.
- Map volumes to the cluster that you created in step 1.
Target ports on XIV Nextra systems
WWNN 2000001738279E00
WWPN 1000001738279E13
WWPN 1000001738279E10
WWPN 1000001738279E11
WWPN 1000001738279E12
Target ports on IBM XIV Type Number 2810 systems
WWNN 5001738000030000
WWPN 5001738000030153
WWPN 5001738000030121