Module 6: Storage Area Network - FC SAN (FC SAN Topologies, Link Aggregation, & Zoning)

Question 1

What is a single switch fabric topology?

Answer 1

fabric has only single switch with both compute and storage systems attached

no ISLs required for compute to storage traffic

every port usable for storage or compute scaling

Question 2

What is a full mesh topology?

Answer 2

each switch is connected to every other switch

max of 1 ISL is required

compute/storage systems can be connected to any switch

Question 3

What is a partial mesh topology?

Answer 3

not all switches are connected to every other switch

several ISLs may be required

Question 4

What is the core-edge topology?

Answer 4

edge tier composed of departmental switches - inexpensive approach to adding more compute

edge tier switches not connected to each other

each edge switch connected to director at core tier through ISLs

Question 5

How are compute systems connected in a core-edge topology where high performance is required?

Answer 5

connected straight to core to minimize hops

Question 6

When is the core-edge topology used?

Answer 6

increases connectivity within FC SAN while conserving overall port utilization

Question 7

What is link aggregation?

Answer 7

combines two or more parrallel ISLs into single logical ISL called a port channel

Question 8

What are the benefits of link aggregation?

Answer 8

yields higher throughput than single ISL can provide

distribute network traffic over ISLs ensuring even ISL utilization

Question 9

How do ports work if there are multiple ISLs between switches in a system but no link aggregation?

Answer 9

fabric assigns an ISL for each of the port pairs in a round robin fashion

Question 10

What is FC SAN zoning?

Answer 10

logical private path between node ports in a fabric

Question 11

What happens when a change in the name server database occurs in a FC SAN fabric?

Answer 11

fabric controller sends Registered State Change Notification (RSCN) to all nodes impacted by the change

if zoning not configured the fabric controller sends RSCN to every node in fabric - can create bottlenecks

Question 12

What is a zone set?

Answer 12

composed of a group of zones that can be activated or deactivated as a single entity in a fabric

multiple zones can be in a fabric but only a few can be on at one time if need be

Question 13

What are the types of FC zoning?

Answer 13

WWN Zoning
Port Zoning
Mixed Zoning

Question 14

What is WWN Zoning?

Answer 14

Uses World Wide Names to define zones - zone members unique WWN of FC HBA and its targets

very flexible zoning procedure

Question 15

What is Port Zoning?

Answer 15

uses the switch port ID to define zones - access determined by the physical switch port to which a node is connected

Question 16

What are the zone members in port zoning?

Answer 16

switch domain ID and port number

Question 17

What is mixed zoning?

Answer 17

combines qualities of both WWN zoning and port zoning - enables specific node port to be tied to WWN of another node

Question 18

What makes WWN zoning considered flexible?

Answer 18

if an admin moves a node to another switch port in fabric node maintains connectivity to zone partners without reconfiguring - WWN is static to the node port

Question 19

What happens if a node is moved to another switch in port zoning?

Answer 19

port zoning must be modified to enable node in new port to participate in original zone - if an FC HBA or storage system port fails admin has to replace failed device w/o changing zone

Question 20

How is a switch fabric managed?

Answer 20

With software - can be just single switch managed by software but normally multiple switches cabled together

Question 21

Where does zoning take place?

Answer 21

At the fabric level

Question 22

What is an inter-switch link (ISL)?

Answer 22

fiber cable used to connect switch ports together in a fabric - typically use more than one for fabric redundancy and performance

Question 23

How are ISLs assigned?

Answer 23

ports assigned one each = more ISLs you have the more data transport paths available

Question 24

What is the disadvantage of a full mesh fabric?

Answer 24

burning more ports in the switch which allows less host/storage connections for scalability