Logical units and target ports on MSA2000 systems
Partitions (volumes) on MSA2000 systems are exported as logical units with a logical unit number that is assigned to that partition.
LUNs on MSA2000 systems
The controller calls an array a volume. SAS and SATA disks cannot be mixed within a volume, and the maximum number of volumes per controller is 16. Volumess can be divided into volumes, which are then presented to the host. There can be up to 128 volumes per controller. The capacity of a volume is between 1 MB and 16 TB.
Storwize® V3700 has an individual 1 PB managed-disk size limit.
LUN IDs
example;
# show volumes
Vdisk Volume Name Size WR Policy Class Volume Serial Number Cache Opt Type
VD0 VD0_V1 750.1GB writeback standard 00c0ffd76a330000a0fa124a01000000 standard standard
VD2 VD2_V1 750.1GB writeback standard 00c0ffd76a33000048fb124a01000000 standard standard
VD_HC VD_CAP_V1 37.5GB writeback standard 00c0ffd76a3300005efc124a01000000 standard standard
VD_1 VD_1_V1 750.1GB writeback standard 00c0ffd7648f000064851d4a01000000 standard standard
VD_3 VD_3_V1 750.1GB writeback standard 00c0ffd7648f0000a6851d4a01000000 standard standard
VD-R VD-R_V1 250.0GB writeback standard 00c0ffd7648f0000aa08234a01000000 standard standard
VD-R VD-R_V2 250.0GB writeback standard 00c0ffd7648f0000ab08234a01000000 standard standard
VD-R VD-R_V3 250.0GB writeback standard 00c0ffd7648f0000ab08234a02000000 standard standard
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# show network-parameters
Network Parameters Controller A
-------------------------------
IP Address : 9.71.47.27
Gateway : 9.71.46.1
Subnet Mask : 255.255.254.0
MAC Address : 00:C0:FF:D7:6A:33
Addressing Mode: DHCP
Network Parameters Controller B
-------------------------------
IP Address : 9.71.47.30
Gateway : 9.71.46.1
Subnet Mask : 255.255.254.0
MAC Address : 00:C0:FF:D7:64:8F
Addressing Mode: DHCP
LUN creation and deletion
- In the Storage Management Utility SMU interface, go to . The SMU provides a wizard to create the volume.
- You have the following options:
- Manual
- Volume Name
- RAID Type Note: Storwize V3700 does not support RAID 0.
- Number of volumes
- Expose to all hostsNote: The Expose to all hosts option can cause confusion in multisystem environments.
- LUN assignments
LUN presentation
You can also use the SMU or the CLI to map and unmap MSA2000 LUNs.
- In the Storage Management Utility SMU interface, go to .
- Under the section Assign Host Access Privileges, select Map Host to Volume.
- For each Storwize V3700 WWPN, select SVC WWPN in the HOST WWN-Name menu.
- Enter the LUN number to present to the Storwize V3700. For example, use 0 for the first volume, then use 1 for the second, until all volumes are assigned.
- Select read-write for the Port 0 Access and Port 1 Access.
- Click Map it. The resulting mapping is
displayed in the Current Host-Volume
Relationships section.Important: Use this section to verify that the LUN ID is consistent and all Storwize V3700 WWPNs have been mapped.
Because there are 8 nodes in the following example, 32 WWPNs show in the show volume-maps output (four ports per node).
example shown for an 8-node cluster, that is, 32 WWPNs;
# show volume-maps
Volume [SN 00c0ffd76a330000a0fa124a01000000, Name (VD0_V1)] mapping view:
CH ID LUN Access Host-Port-Identifier Nickname
-------------------------------------------------------------------------------
0,1 0 0 rw 50050768012FFFFF
0,1 0 0 rw 5005076801105CEE
0,1 0 0 rw 500507680110008A
0,1 0 0 rw 50050768011FFFFF
0,1 0 0 rw 50050768013FFFFF
0,1 0 0 rw 50050768014FFFFF
0,1 0 0 rw 500507680140008A
0,1 0 0 rw 500507680130008A
0,1 0 0 rw 500507680120008A
0,1 0 0 rw 5005076801405CEE
0,1 0 0 rw 5005076801205CEE
0,1 0 0 rw 5005076801305CEE
0,1 0 0 rw 500507680110596B
0,1 0 0 rw 5005076801305FB8
0,1 0 0 rw 5005076801205FB8
0,1 0 0 rw 5005076801405FB8
0,1 0 0 rw 5005076801105FB8
0,1 0 0 rw 500507680120596B
0,1 0 0 rw 500507680140596B
0,1 0 0 rw 500507680130596B
0,1 0 0 rw 5005076801400009
0,1 0 0 rw 5005076801300009
0,1 0 0 rw 5005076801100009
0,1 0 0 rw 5005076801200009
0,1 0 0 rw 50050768014FFFFE
0,1 0 0 rw 50050768013FFFFE
0,1 0 0 rw 50050768012FFFFE
0,1 0 0 rw 50050768011FFFFE
0,1 0 0 rw 5005076801200001
0,1 0 0 rw 5005076801400001
0,1 0 0 rw 5005076801300001
0,1 0 0 rw 5005076801100001
Special LUNs
Volumes can have a LUN ID from 0 to 126 on each controller. LUN 0 on the MSA2000 is visible from both controllers, but can only be used to access storage from the preferred controller. LUN 0 on the other controller does not present storage.Target ports on MSA2000 systems
The MSA2000 system has two dual-active controllers with two ports each. You must set these as point-to-point using the SMU interface.
In the Storage Management Utility SMU interface, go to
. Select Advanced Options and specify point to point for Change Host Topology.Each WWPN is identified with the pattern 2P:7N:CC:CC:CC:MM:MM:MM where P is the port number on the controller and N is the address of the controller port (0 or 8), CC:CC:CC represents the Organizationally Unique Identifier (OUI), and MM:MM:MM is unique for the particular controller.
example;
# show port-wwn
CTRL CH WWPN
-------------------------
A 0 207000C0FFD75198
A 1 217000C0FFD75198
B 0 207800C0FFD75198
B 1 217800C0FFD75198
LU access model
The MSA2000 is a dual-active system. Each LUN has an owning controller, and I/O is serviced only by ports on that controller. Failover automatically takes place when one controller fails (shuts down). There is no way for Storwize V3700 to force failover.
LU grouping
The MSA2000 system does not support LU grouping.
LU preferred access port
The MSA system has two ports per controller. The I/O is through port 0, and port 1 is linked to port 0 of the other controller during a failure or a code upgrade.
Detecting ownership
The LUN is reported only by the target ports of the owning controller.