HOTSPOT
A company has servers that run Windows Server 2008 R2 and a storage area network (SAN) that
supports the virtual Disk Service (VDS). You are designing a storage solution for the servers. The
storage solution must meet the following requirements:
• Allow the creation of Fibre Channel (FC) and Internet SCSI (iSCSI) logical unit numbers
(LUNs).
• Allow the management of FC and iSCSI LUNs.
You need to ensure that the storage solution meets the requirements. Which feature should you
install?
To answer, select the appropriate feature in the answer area.
Answer: 
Explanation:
Storage Manager for SANs helps you create and manage logical unit numbers (LUNs) on Fibre
Channel and iSCSI disk drive subsystems that support Virtual Disk Service (VDS) in your storage area
network (SAN).
A LUN is a logical reference to a portion of a storage subsystem. A LUN can comprise a disk, a section
of a disk, a whole disk array, or a section of a disk array in the subsystem. Using LUNs simplifies the
management of storage resources in your SAN because they serve as logical identifiers through
which you can assign access and control privileges.
You can use Storage Manager for SANs to create and manage logical unit numbers (LUNs) on both
Fibre Channel and iSCSI disk storage subsystems that support Virtual Disk Service (VDS).
Because of hardware, protocol, and security differences, LUN configuration and management on
Fibre Channel and iSCSI environments is different. This section explains those differences, lists the
types of LUNs that can be created, and defines LUNs in the context of partitions and volumes.
Managing LUNs in a Fibre Channel environment
In a Fibre Channel environment, LUNs created on a disk storage subsystem are assigned directly to a
server or cluster, which accesses the LUN through one or more Fibre Channel host bus adapter (HBA)
ports. You only need to identify the server or cluster that will access the LUN, and then select which
HBA ports on that server or cluster will be used for LUN traffic.
When a server or cluster is identified, Storage Manager for SANs automatically discovers the
available Fibre Channel HBA ports on that server or cluster. You can also add ports manually by
typing their World Wide Name (WWN).
Managing LUNs in an iSCSI environment
Unlike in a Fibre Channel environment, LUNs created on an iSCSI disk storage subsystem are not only
assigned to a server or cluster. For iSCSI, LUNs are first assigned to logical entities called targets.
Targets are created in order to manage the connections between an iSCSI device and the servers
that need to access it. A target defines the portals (IP addresses) that can be used to connect to the
iSCSI device, as well as the security settings (if any) that the iSCSI device requires in order to
authenticate the servers that are requesting access to its resources.
To connect to a target, a server in the storage area network (SAN) uses an iSCSI initiator. An iSCSI
initiator is a logical entity that enables the server to communicate with the target. The iSCSI initiator
first logs on to the target, and only after access is granted by the target, the server can start reading
and writing to LUNs assigned to that target. Each iSCSI initiator can have one or more network
adapters through which communication is established.
As with Fibre Channel environments, you only need to identify the server or cluster that will access
the LUN, and Storage Manager for SANs automatically discovers the iSCSI initiators on that server or
cluster, and lists all the available adapters for those initiators. After the iSCSI initiator adapters have
been discovered, you can select which adapters will be used for LUN traffic.
Types of LUNs
Storage Manager for SANs supports the following types of LUNs.
LUNs, partitions and volumes
A LUN is a logical reference to a portion of a storage subsystem. A LUN can comprise a disk, a section
of a disk, a whole disk array, or a section of a disk array in the subsystem. This logical reference,
when it is assigned to a server in your SAN, acts as a physical disk drive that the server can read and
write to. Using LUNs simplifies the management of storage resources in your SAN, because they
serve as logical identifiers through which you can assign access and control privileges.
After a LUN has been assigned to a server, you can create one or more partitions on that LUN.
Partitions define how much physical space is allocated for storage. For the operating system to start
writing and reading data on partitions, you need to create volumes by formatting the partitionsusing a file system. Volumes define how much logical space is allocated for storage. They can expand
over more than one partition.
