Essential Guide

LUN storage: Working with a SAN's logical unit numbers

A complete guide to everything you need to know about LUN implementation and management.


In a SAN fabric, LUN storage is essential to the configuration of the environment and its performance. A LUN is a unique identifier given to separate devices, or logical units, so they can be accessed by a SCSI, iSCSI or Fibre Channel protocol. LUNs are key to disk array configuration because disks are typically defined in sets of RAID groups to protect against failure; however, those RAID groups can't be presented to the host. By assigning LUNs, all or a portion of a RAID group's capacity can be presented to the host as individual, mountable volumes.

For IT pros, implementing LUN storage involves a number of decisions, such as the number of LUNs to be created, what size they will be and what hardware the LUNs will live on. Additionally, techniques such as LUN masking and LUN zoning can be used to dictate which hosts have access to which LUNs.

This guide walks you through all these issues by explaining how LUN storage works, the basics of implementation and best practices for management.

1Understanding LUN storage-

LUN storage and how it works

At a basic level, LUNs are a reference to specific storage in a SAN. A LUN can represent a hard disk drive (HDD), a portion of an HDD or even a full storage array. LUNs are essential to the management and efficiency of your storage because they dictate which hosts will access which storage. The following links provide a closer look at how LUN storage works and how certain configurations can affect the performance of your storage environment.


Defining the logical unit number

Learn exactly what a logical unit number is, the origin of the term and how it works with iSCSI environments. Continue Reading


What makes LUN storage important?

Why do we need LUN storage rather than using disks as they are? Find out how a LUN works in this answer from storage expert Randy Kerns. Continue Reading


LUN storage FAQ: Answers for IT pros

Expert Brien Posey answers five questions storage administrators have about LUN storage in their environments. Continue Reading


Understanding virtual LUNs

Because virtual LUNs are not tied to physical devices or allocations, an administrator can create large numbers of them that will be allocated only when the data is written. Continue Reading

2Implementing LUNs-

Best practices to ensure efficient LUN implementation

Because one LUN can be shared by numerous hosts or vice versa, you need to consider how big a LUN will be and how many LUNs a single host can access. Other important implementation considerations include which RAID levels get the best performance for their cost and whether to use technologies such as thin provisioning, tiering or data deduplication. The material below describes how to approach each of these decisions and their effect on a SAN environment.


LUN configuration best practices

LUN configuration plays a key role in tweaking virtual machine (VM) performance. Learn how the hardware, disk type and RAID level of LUN storage help run more VMs per host. Continue Reading


How to determine the amount of VMs to put on a LUN

LUN storage can improve virtual machine performance. When deciding how many VMs to put on a LUN, the size of your infrastructure is an important consideration. Continue Reading


Understanding LUN zoning and LUN masking

Masking and zoning are two common practices with LUN storage that affect LUN access. This expert answer explains which practice is best for a SAN fabric. Continue Reading


Strategies for LUN management

This tip explores the background of LUN storage, the different LUN features vendors have to offer and how to determine which type of LUN is best for you. Continue Reading

3LUN management-

Using LUNs to ease storage management

Typically, all LUN storage can be managed through one software program that specifies the path between LUNs and hosts. However, management best practices can differ depending on the type of environment used -- Fibre Channel versus iSCSI storage, for example. The following tips outline some best practices for managing LUN storage.


The fundamentals of LUN management

IT expert Brien Posey discusses five fundamental ideas storage professionals must understand when managing LUN storage. Continue Reading


Top tips for managing LUNs in a VMware environment

In a VMware environment, LUN management can be a critical factor in optimizing storage capacity and performance. These 13 best practices for managing LUNs with VMware will help you get the most out of your LUN storage. Continue Reading

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How can we assign an specific IP for the partitioned LUN?