LUN and Volume

LUN and Volume are two different and identical concepts:

Different:

1) Voume is generally used for storage. Generally, the concept of Volume is used for initial "Bare" disk operations by storage management software;
2) When the disk RAID and capacity are well divided, ing Mapping should be performed on the connected hosts. At this time, a LUN number should be assigned to the host;
3) The LUN number is recognized for the OS. The OS Format is generally the Drive we see;

Same:

Identity of the same object in two systems respectively

LUNRelationship with VOLUME

LUN is for storage devices and volume is for hosts.
How can we understand it?
Select multiple hard disks on the storage device to form a RAID group, and then create one or more Luns Based on the RAID group to create one LUN ). The storage devices of many vendors only support creating one LUN on one RAID group. In this case, the LUN is a logical device relative to the storage device.

When a host on the network is connected to a storage device, it can identify the logical device LUN on the storage device. At this time, the LUN is a "physical hard disk" relative to the host ", it is the same as the local data center or SCSI hard disk where drive C is located. Create one or more partitions on the "physical hard disk" and then create a file system to obtain a VOLUM. VOLUME is a logical device relative to the host.
Compare VOLUME in terms of capacity. The relationships among partitions, Luns, and RAID are as follows:
VOLUME = partition ≤ disk in the host Device Manager = LUN ≤ RAID ≤ total disk capacity of the storage device.
The above is only for general cases, and VOLUME is only for the host. The LUN and VOLUME definitions of individual vendors are different from those of general vendors, and even some strange names are not necessarily clear. But as long as you can clearly identify the essence.
Therefore, when learning about storage, we also appeal to all vendors to standardize product names and unify their concepts. However, it is estimated that only after a vendor unifies the entire storage market can it be achieved, as if Qin Shihuang unified the six countries before unified measurement units and currencies.