The Lenovo Storage V7000 solution is based on a group of virtualization concepts. Before setting up your Lenovo Storage V7000 environment, you must understand the concepts and the objects in the environment.
Each single processing unit is a node canister, which is also called a node. The two nodes within the canisters make an I/O group that is attached to the SAN fabric.
Volumes are logical disks that are presented by the systems. Each volume is associated with a particular I/O group. The nodes in the I/O group provide access to the volumes in the I/O group. When an application server performs I/O to a volume, it can access the volume with either of the nodes in the I/O group. Because each I/O group has only two nodes, the distributed cache is only two-way.
The node canisters are connected to the drives inside the enclosures. The drives are used to create one or more Redundant Arrays of Independent Disks (RAID). These arrays are also known as managed disks (MDisks).
The system is also able to detect logical units that are presented by back-end storage systems as MDisks.
Each MDisk is divided into a number of extents which are numbered, from 0, sequentially from the start to the end of the MDisk.
MDisks are collected into groups, known as storage pools.
Each volume is made up of one or two volume copies. Each volume copy is an independent physical copy of the data that is stored on the volume. A volume with two copies is known as a mirrored volume. Volume copies are made out of MDisk extents. All the MDisks that contribute to a particular volume copy must belong to the same storage pool.
A volume can be thin-provisioned. This means that the capacity of the volume as seen by host systems, called the virtual capacity, can be different from the amount of storage that is allocated to the volume from MDisks, called the real capacity. Thin-provisioned volumes can be configured to automatically expand their real capacity by allocating new extents.
At any one time, a single node in a system can manage configuration activity. This node is known as the configuration node and manages a cache of the information that describes the system configuration and provides a focal point for configuration.
For a SCSI over Fibre Channel or Fibre Channel over Ethernet (FCoE) connection, the node canisters detect the FC or FCoE ports that are connected to the SAN. These correspond to the worldwide port names (WWPNs) of the FC or FCoE host bus adapters (HBAs) that are present in the application servers. You can create logical host objects that group WWPNs that belong to a single application server or to a set of them.
The system identifies host server iSCSI, SAS, and Fibre Channel ports by world wide port name (WWPN) and iSCSI hosts by iSCSI qualified name (IQN).
For a SCSI over Ethernet connection, the iSCSI qualified name (IQN) identifies the iSCSI target (destination) adapter. Host objects can have both IQNs and WWPNs.
Lenovo Storage V7000 hosts are virtual representations of the physical host systems and application servers that are authorized to access the system volumes. Each Lenovo Storage V7000 host definition specifies the connection method, the port or IQN, and the volumes that the host applications can access.
The system provides block-level aggregation and volume management for disk storage within the SAN. The system manages a number of back-end storage systems and maps the physical storage within those storage systems into logical disk images that can be seen by application servers and workstations in the SAN. The SAN is configured in such a way that the application servers cannot see the back-end physical storage. This prevents any possible conflict between the system and the application servers both trying to manage the back-end storage.