Storage Area Networks SAN basic L1 and L2 interview question and answers


Storage Area Networks (SAN) has huge requirements and the popularity and importance of this technology is increasing every year. According to my knowledge EMC and IBM are good among this technology and they recruit lots of junior level SAN administrators. 

In this post I have posted some of the basic SAN interview questions collected from various candidates. This should really help the SAN newbies....The best practise is always try to research and find out your own answers and not relying on someones answers....

SAN Storage Administrator L1 Interview Question and Answers

1. What is a SAN?
A SAN is a dedicated network for sharing storage resources. A SAN provides accelerated data access and supports advanced storage management.

2. Name 3 Limitations of DAS Technology?
No scalability, I/O Bottleneck, Limitations in cable length, Unable to share resource

3. Name at least 4 of the Hardware component in a SAN?
Cable, SAN Switch, GBIC, Storage Subsystem, Host Bus Adapters

4. How could implementation of a SAN benefit LAN performance?
High Speed, Long distance, Data Travel with in the SAN, Fast access Data Backup, Improved Performance

5. Name 3 key features of Fibre Channel?
High Speed, Long distance, Data Travel with in the SAN, Fast access Data Backup, Improved Performance.

Also Read: Storage Area Network (SAN) Basic Free Tutorials

6. How is a SAN Superior to SCSI?
SAN offers a number of advantages to parallel SCSI. Fibre Channel is substantially faster than parallel SCSI. In addition, Fibre Channel supports both Fibre Optic and copper cabling at distances of up to 10 Kilometers. It also connects up to 127 nodes on an Arbitrated Loop and up to 16 million nodes on a Fibre Channel Switch. With its ability to map IP, Fibre Channel is significantly more than a parallel SCSI replacement. Fibre Channel’s IP support gives its networked storage devices access to multiple servers or nodes for accelerated data access and enhanced data management.

7. What is a Point-to-Point Topology?
Point-to point topology provides a simple, direct connection between just two nodes. This topology is the closest approximation to the traditional SCSI topology and provides a direct connection between two nodes, such as between a file server and a disk subsystem. With this topology, the transmitter port on one node os connected directly to the receiver port on the other node.

8. What is FC-AL?
FC-AL is a abbreviation for Fibre Channel – Arbitrated Loop. FC-AL is a industry standard topology that links up to 126 ports together on a single shared simplex media. Transmissions can only occur between a single pair of nodes at any given time. Arbitration is the scheme that determines which node has control of the loop at any given moment.

9. What is Switched or Switched Fabric Topology?
A Fibre Channel Switch permits multiple simultaneous transmissions between pairs of nodes connected to it. The data is switched from the source node to the destination node.

10. What is the “Fabric” in a Switched Fabric Topology?
In the early days of Fibre Channel, the concept of a universal “Fabric” was used to support Fibre Channel’s topology independence. With the advent of point-to-point and FC-AL topologies, it’s value has been enhanced.The Fibre Channel Fabric was designed as a generic interface between each node and the physical layer interconnection of the nodes. By adhering to this interface, any Fibre Channel node could communicate over the “Fabric” without having to know the interconnecting scheme between nodes. A “Fabric” is similar to a telephone switch which allows you to originate a call to another party without requiring you or the other party to have detailed information about the interconnection mechanism used to establish the call between two points.

11. Where does SAN fit into Today’s Networking Environment?
SANs compliment today’s LAN and WAN technologies by acceleration functionality and performance behind the server, where current LAN and WAN technology leaves off. They also compliment the ongoing advancements in LAN and WAN technologies by extending the benefits of improved performance, topological flexibility and remote management from the client and backbone to servers and storage.

Unlike traditional LAN and WAN technologies, the gigabit speed of a Fibre Channel-based SAN accelerates I/O performance, relieving the burden from servers in the tiered client/server architecture. SANs also support advanced storage management features that include highspeed remote back-up and data mirroring. They also provide a platform for server clustering to migrate into the open market.

Also Read: DAS vs SAN vs NAS

12. What type of san switch you are using?
Brocade, Mc Data, so on

13. What is the command to measure the speed of the port?
      #show port 2

14. What you mean by lun masking?
Hiding the luns to specific to host

SAN Storage Administrator L2 interview question and answers:

1. What is the difference between Raid 1 and Raid 5?
 Mirroring and Parity striping across the disks.

2. What is the difference between Lun masking and Zoning?
Lun masking is hiding the LUN to specific server or Host and Zoning is specific to Operating system for e.g Windows zoning, UNIX zoning only preferred luns can be assigned to particular Zoning

3. Give examples of few CLI commands of the Storage controller?
Different for Different storage

4. What is the meaning of IOPS? Where it plays important role?
IOPS INPUT OUTPUT PER SECOND One transaction to and fro of the server to storage. Mission critical applications planning based on IOPS one can determine the storage,space needs.

Also Read:  AIX Basic concepts and commands

5. Give an example of the Database configurations for Disk layout?
It differ storage to storage expected answer Raid 1+0 configurations

6. Name at least 3 ways consolidating storage improves operational efficiencies. ?
Centralized administration, Scalability, Backup/restore improvement

7. What advantages do LAN-free back up and restore deliver?
Speed up the backup/Restore, Data will not travel over LAN

8. Name at least 3 ways a SAN provides a High Availability Infrastructure.
No single point of failure, BACKUP/Restore speed, Replication/DR will be improved from Distance point of view

9. What are the steps involved to accomplish Raid best configurations?
Size of the data, no of users, criticality of applications, cost effective of the storage requirements, Raid 1+0

10. What is the functionality of multi pathing?
Load balancing, fail over on different path, security




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7 Responses to "Storage Area Networks SAN basic L1 and L2 interview question and answers"

  1. great post.

    Thanks
    Sushil

    ReplyDelete
  2. As a networking student it will be helpful for me. Because your all question needed to me. Thanks.

    wide area network

    ReplyDelete
  3. Its great to have these type of question along with answers.. Thanks

    ReplyDelete
  4. Its great to have these type of question along with answers.. Thanks

    ReplyDelete
  5. Very nice .... Thanks

    ReplyDelete
  6. Very nice to have look over for interview purpose

    Good job

    ReplyDelete