Logical units and target ports on NetApp E-Series storage systems

LUNs are provisioned from the NetApp E-Series as volumes. These LUNs appear as MDisks on the system, which can be used to create storage pools and provision volumes for use by hosts or with tiering.

LUN size

For regular volume groups, the maximum volume size is limited only by the size of the drives and the maximum number of drives in the volume group based on the RAID level. For an example, in RAID 5 and RAID 6 volume groups, the maximum number of drives in the volume group is 30. For Dynamic Disk Pool, the maximum volume size is 64 TB.

LUN mapping

NetApp E-Series can export 256 LUNs to the system, which is the limit. The system supports greater than 2 TB LUNs and has a maximum LUN size of 1 PB.

LUN IDs

NetApp E-Series systems identify exported logical units through SCSI identification descriptor type 3. The 64-bit NAA IEEE Registered Extended Identifier (NAA=6) for the logical unit is in the form 6-OUI-VSID. The LSI NetApp E-Series IEEE company ID is 0x00A0B8. NetApp E-Series IEEE company ID is 0x0080E5. The remaining part of the company ID is a vendor-specific ID.

System configuration (includes logical drives and hosts)

In general, settings are default unless specified. For more information, see the information about NetApp E-Series configuration settings.

LUN modification, resizing, or deletion

Before you make modifications on the system, you must remove the LUN from any system storage pool and the LUN must be in an unmanaged state.

Note:

Make sure the MDisk is unmanaged (removed from any storage pool) on the system before you delete the LUN on the NetApp E-Series storage system.
Do not use array expansion on LUNs that are in use by a system. To be recognized by the system, the MDisk must first be made unmanaged by migrating or deleting from the storage pool.

LUN presentation

LUNs are exported through the available FC ports of the NetApp E-Series storage system. Configure these LUNs explicitly. Do not use default mapping to guarantee unique system access.

Special LUNs

Logical unit numbering has no special considerations. LUN 0 can be exported where necessary.

The access LUN, also known as the Universal Transport Mechanism (UTM) LUN, is the configuration interface for NetApp E-Series systems. The access LUN might not be in a partition that contains the system ports because it is not required by the system. The UTM LUN is a special LUN that allows NetApp E-Series systems to be configured through suitable software over the Fibre Channel connection.

Because the system does not require the UTM LUN, it does not generate errors either way.NetApp E-Series systems must not have the Access UTM LUN that is presented as LUN 0 (zero).

It is possible to use in-band (over Fibre Channel) and out-of-band (over Ethernet) to allow the configuration software to communicate with more than one NetApp E-Series system. If you are using in-band configuration, configure the Access UTM LUN in a partition that does not include any logical units that are accessed by Lenovo Storage V series.

Note: In-band is not supported for access to the LUN while in the system partition.

Target ports

A NetApp E-Series storage system has a total of eight Fibre Channel ports (four ports on each controller) with the following speed levels:

E26xx: 8 Gb FC
E54xx: 8 Gb FC
EF540: 8 Gb FC
E27xx: 16 Gb FC
E55xx: 16 Gb FC
EF550: 16 Gb FC

Example of a WWNN and WWPN:

20020080e5290640:  WWNN
20120080e5290640: so this a WWPN for Port 1 on Controller A
20430080e5290640: so this a WWPN for Port 4 on Controller B

For more information about target ports, see Storage array profile on the summary tab in the NetApp SANtricity Storage Manager GUI.

LU access model

All systems are Asymmetric Active/Active. To avoid an outage from system failure, cross connect the ports across Fibre Channel switches. Because all model NetApp E-Series storage systems are equal in priority, you gain no benefit by using an exclusive set for a specific LU.

LU preferred access port

The model NetApp E-Series has no preferred access ports, as all ports are Asymmetric Active/Active across all controllers.