CNIT 242 Exam 2: Storage Services Part 3

What is RAID?

Redundant Array of Inexpensive Disks that are used to create a single logical disk from multiple physical disks.

Why use RAID?

To increase performance and for fault tolerance

T/F: RAID is only implemented in hardware.

False, they can be implemented in hardware or software

How does hardware RAID work?

RAID operations are managed by the attachment controller and don’t use processor clock cycles or memory

What does Hardware RAID create?

A single point of failure, if the RAID controller fails, the entire array is down

How is Software RAID performed?

By the OS and uses processor clock cycles and memory

T/F: Physical drives are partitioned into special RAID partitions with hardware RAID

False, they are partitioned into special RAID partitions with software RAID

What is RAID 0

Striping, meaning data is distributed across multiple disks and provides performance, but no redundancy

T/F: In RAID 0, if one disk fails, all data is lost

True

What is RAID 1?

Mirroring, meaning data is duplicated across multiple disks providing no increased performance, but is fault tolerant

T/F: In RAID 1, if one disk fails, all data is lost.

False, a copy can be used

What is RAID 5?

Striped with parity, meaning data is striped across multiple disks and parity data is kept for each set of stripes. Increases performance and provides some redundancy.

What is RAID 10?

Striped and mirrored, meaning it stripes data across multiple disks which are then mirrored, which increases performance and is fault tolerant

What is Network Attached Storage (NAS)?

File level storage that is available over the network and is already partitioned and formatted.

T/F: NAS doesn’t require dedicated hardware

True, ethernet is the transport of choice

What are some common NAS technologies?

SMB, Common Internet File System, NFS

What is Storage Area Networks (SAN)?

Block level storage accessible over a network that uses dedicated hardware to interconnect the storage arrays

T/F: A physical connection is required for SAN

True

What are some SAN technologies?

iSCSI, Fiber Channel

What is SAN typically used for?

Datacenter-class applications because they separate traffic on networks

What is NAS typically used for?

File server applications, and the traffic is shared with other traffic

What is iSCSI?

Internet Small Computer System Interface, which is an OSI Session layer protocol

T/F: iSCSI uses UDP as the protocol and is not routable

False, uses TCP and is routable

What is an initiator in iSCSI?

A device that originates a session to a storage device and is typically a computing host

What is a target in iSCSI?

The storage device to which an intiator connects which is typically a dedicated device offering network storage

T/F: A single target is accessed by a single initiator in iSCSI

False, a single target can be accessed by multiple initiators

What is a Logical Unit Number (LUN)?

A logicial drive/partition presented over the network.

T/F: Each target contains multiple LUNs

True

What is network fabric?

The interconnection betweens nodes, typically ethernet

How are iCSI initiators and targets named

By iQNs or extended Unique Identifiers

T/F: In iSCSI, the network storage devices must be enumerated before they can be accessed

True

What is SendTargets in iSCSI?

A target server is queried by the initiator for the list of available targets and requires no additional infrastructure or services

In iSCSI security, what are the 4 componenents of it?

Logon, authentication, authorization, and encryption.

Which componenents of iSCSI security are optional?

Authentication and encryption

T/F: Initiators don’t have to logon to targets.

False, they must logon to targets

What is the process in iSCSI Logon?

Initiators create a connection and open a session, the first PDU sent must be a login request else the connection must be terminated by the target.

T/F: Until the login is completed, no other PDUs can be exchanged in the iSCSI logon process

True

T/F: The logon process can carry on if another PDU is received by the target.

False, it must fail the logon

iSCSI Authentication is provided by what?

Challenge-Handshake Authentication Protocol (CHAP)

What differentiates one way CHAP with mutual CHAP?

One way chap is when the target authenticates the initiator and mutual chap is when the target and initiator authenticate each other

Which CHAP is the minimum authentication level that should be used in protection?

One way CHAP

T/F: Authentication must be used in development in iSCSI Authentication

False, it’s ok to use no authentication in development

What is iSCSI Authorization based on?

Based on iQN, eui, IP address

How does iSCSI Authorization work?

The target checks ACL to determine if access to target is allowed

T/F: ACLs can be wildcarded to allow anyone access in iSCSI Authorization

True