A LUN (Logical Unit Number) is used to allow clients to access and interact with storage space, primarily on a Storage Area Network (SAN), for tasks such as data storage, retrieval, and network drive mapping.
Here's a breakdown of the reasons why you'd use a LUN:
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Provides Addressable Storage: A LUN is essentially a unique identifier for a logical unit of storage. It allows the SAN to present a block of storage to a server in a way that the server can recognize and use it as a disk drive. Without LUNs, servers would not be able to distinguish between different storage volumes on the SAN.
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Simplified Storage Management: LUNs abstract the physical storage complexity from the servers accessing the storage. Administrators can manage the underlying storage (RAID configuration, disk types, etc.) without affecting how the servers interact with the LUNs.
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Efficient Storage Allocation: LUNs enable you to allocate storage space on demand to different servers or applications. This allows for efficient use of storage resources, as you can provision only the amount of storage needed.
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Centralized Storage: By using LUNs on a SAN, you centralize storage management. This simplifies tasks such as backups, disaster recovery, and storage upgrades.
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Performance and Scalability: SANs, and therefore LUNs, can provide high performance and scalability. SANs can support faster network connections (e.g., Fibre Channel, iSCSI) and can be easily expanded as storage needs grow.
Use Cases:
- Databases: LUNs are commonly used to store database files, providing the necessary performance and reliability for database applications.
- Virtual Machines: Virtual machine images are often stored on LUNs, allowing for centralized management and high availability.
- File Servers: LUNs can be used to provide storage for file servers, allowing users to share files across a network.
- Applications: Any application that requires persistent storage can benefit from using LUNs.
In essence, a LUN provides a manageable, addressable, and scalable way for servers to access and utilize storage resources on a SAN.
