A LUN ID in storage is a unique identifier for a Logical Unit Number (LUN), which represents a distinct and addressable portion of storage space presented to a server from a storage area network (SAN) or other storage system. Think of it as a specific "drive letter" assigned to a storage volume within the SAN.
Understanding LUNs
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Logical Unit Number (LUN): A LUN isn't a physical storage device itself. Instead, it's a logical designation that allows a server to recognize and access a specific block of storage. It's a virtual representation of storage space.
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LUN ID: The LUN ID is the address used to identify a particular LUN. The server uses this ID to locate and communicate with that specific storage allocation.
How LUN IDs Work
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Storage Array Configuration: A storage administrator configures a storage array (e.g., a SAN) and carves out portions of the physical storage into LUNs.
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LUN Assignment: Each LUN is assigned a unique LUN ID. This ID acts as its address within the storage system.
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Server Mapping: The administrator maps these LUNs to specific servers. This mapping allows the server to "see" the storage as if it were directly attached.
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Server Access: The server uses the LUN ID to communicate with the storage array and access the data stored on that specific LUN.
Example
Imagine a large warehouse (the storage array). The warehouse is divided into numbered storage units (LUNs), each with a unique unit number (LUN ID). A delivery truck (server) needs to pick up goods from a specific unit. It uses the unit number (LUN ID) to locate the correct storage unit within the warehouse.
Significance of LUN IDs
- Organization: LUN IDs are crucial for organizing and managing large amounts of storage.
- Access Control: They allow administrators to control which servers have access to specific storage volumes.
- Scalability: LUNs provide a scalable way to add and manage storage as needed.
- Flexibility: They offer flexibility in allocating storage resources to different servers and applications.
In Summary
The LUN ID is the essential address that a server uses to locate and access a specific, logically defined storage volume within a SAN or other storage system. It is a key element in storage management, providing organization, access control, and scalability.
