Chapter 12


1:

What is the primary function of storage virtualization?

A1:

Answer: To create upstream storage address spaces from downstream storage address spaces

2:

What is the similarity between a SAN virtualization system and a storage subsystem?

A2:

Answer: A SANvirtualization system is similar to placing the subsystem controller in the SANinstead of in a subsystem cabinet.

3:

How do volume managers and SAN virtualization systems differ in their "view" of the network?

A3:

Answer: SANvirtualization systems work with multiple hosts, and volume managers work with a single host.

4:

Describe the difference between concatenation and striping.

A4:

Answer: Concatenation appends a storage address space to another, and striping intertwines strips of different address spaces.

5:

What is the difference between fan-in and fan-out of a SAN virtualization system?

A5:

Answer: Fan-in is the number of simultaneous initiator/target connections available through a single port. Fan-out is the number of downstream LUNs used to form a single upstream LUN.

6:

How can high utilization of storage lead to poorer I/O performance?

A6:

Answer: It causes disk fragmentation, which leads to longer seek times and the creation of hot spots on disk drives.

7:

True or false: Storage subsystems have more predictable connection environments than volume managers or SAN virtualization controllers.

A7:

Answer: True

8:

Starting with the filing system and looking downstream, name the elements of the I/O software stack in a host system.

A8:

Answer: Filing system, volume manager, multipathing software, SCSIcommand driver

9:

If a SAN virtualization system is a single point of failure, what can be done to improve availability?

A9:

Answer: Operate two or more virtualization systems in a cluster configuration.



Storage Networking Fundamentals(c) An Introduction to Storage Devices, Subsystems, Applications, Management, a[... ]stems
Storage Networking Fundamentals: An Introduction to Storage Devices, Subsystems, Applications, Management, and File Systems (Vol 1)
ISBN: 1587051621
EAN: 2147483647
Year: 2006
Pages: 184
Authors: Marc Farley

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