Technical Interview Round for Storage & SAN Support engineer

I had to wait for nearly 40 minutes for the secound round of Technical interview. Read previous post (below post) Wipro Storage Interview to know what they asked in HR round.

There were very few guys in storage/SAN who came for this interview though it was a widely publicised walkin. There were more than 60 guys each for Software Testing, Java Development, Dotnet programming , Oracle ,Networking etc but for Storage hardly 5 guys came for the interview. This boosted my confidence - I was already imagining that I will definitely be given offer letter. Read the full posts to get all the details of this experience.

Second round was taken by two guys one seemed like a lead & another an engineer with little experience. Lead asked most of the questions & the new engineer asked twisted questions out of my own answers - it was more of a verification of my confidence in the subject.

Questions asked in that technical round of interview were like:
1. What kind of Storage Solutions have you worked on ?
2. Describe customer scenarios which you worked in & what problem did I resolve with my Storage knowledge ?
3. What Storage subsystems I have working experience on ?
4. Which vendor equipments I've used ?
5. How did you configure a SAN box from scratch ?
6. How do I plan , provision & manage Lun creation for different teams withing an organization ?
7. What are the difficulties I've faced in optimally utilizing the Storage infrastructure ?
8. What troubleshooting I've done & what are the steps I've followed ?
9. How different is it to manage a FC SAN & an iSCSI SAN ?
10.Mentioned some of the major company Storage products mention their specifications , limitations & performance comparisons ?
11. How will I manage if I have to work with Vmware Virtualization in my infrastructure do I have any exposure with ESX Server Administration or with Virtual Infrastructure management ?
12. What are the High Availability (HA) & Disaster Recovery Solutions (DR) I've implemented & how did I work out all the initial planning,designing,implementation & maintenance?
13. What is Zoning ? Mention types of Zoning & What Zoning options are available in which company products ?
14. What is Storage Virtualization & Storage Consolidation ?
15. Explain RAID5,RAID50,RAID10,RAID6,RAID3 which one is prefered & when ?

More details about how the interview went on will be posted in next 30 minutes keep reading .

Dont forget to see job openings for Storage in EMC2,HP,Wipro & many major companies in Storage Jobs Blog

For People who are interested to learn manual application Testing find real company Testing Interview Questions by clicking Testing Materials Website

Solaris Interview Questions from Real Storage Company Interviews

21) How will you use “shutdown” command?
A) # shutdown –i0 –g300 –y

22) How will you check the OBP version of your system ?
A) Use “ banner” command at the ok prompt

23) Explain the Solaris Boot process?
A) 23.1 ) Boot Prom Phase : Runs POST to verify system hardware and memory Loads “bootblk” primary boot program.
23.2) Boot Program Phase : “bootblk” loads the finds “ufsboot” and loads it in memory.ufsboot loads the kernel.
23.3) Kernel Initialization Phase : Loads modules using “ufsboot”
Creates user processes and starts /sbin/init process.
23.4) Initialization Phase : Starts “rc” scripts. These scripts check & mounts file System, starts various processes and perform system maintanence tasks

24) Backup And Restore :
Full backup : # ufsdump 0uf /dev/rmt/0 /
Where 0 à indicates full backup f à Path of the backup device u à update the dumpdates file.
Restore : # ufsrestore if /dev/rmt/0

25) How to temporary disable user’s login.
A) Log in as “root”
B) Create /etc/nologin file
# vi /etc/nologin
C) Include a message
D) Close and Save the file.

26) What does ‘Probe’ command do?
A) probe-scsi-all à list all internal and external scsi devices
B) probe-ide-all à List all ide devices

27) How to find whether a system is configured for 32-bit or 64-bit?
A) # isainfo -v

28) How to activate Ethernet card ?
A) # ifconfig qfe0 plumb

29) How will you assign ip address to system?
A) # ifconfig qfe0 192.168.0.1 netmask 255.255.255.0 up

30) How will you check current ip configuration?
A) # ifconfig –a

I encourage the blog readers to share their IT work experience & any interview tips or interview questions - anyone who sends original articles will get 4 FREE downloadble Storage Study materials. Thanks Dushyant (scorpio) for sharing above interview questions on Solaris

What is iSCSI Storage Solution Is it one of the Top Storage Technologies

Email roger.smithson@gmail.com for a FREE SAN STUDENT GUIDE pdf file


If you aspire to be a professional in Storage IT company its a MUST to know FC & iSCSI. There was a previous post about FC & below is a brief on iSCSI .
As per Wikipedia's definition Internet SCSI (iSCSI) is a network protocol standard, officially ratified on 2003-02-11 by the Internet Engineering Task Force, that allows the use of the SCSI protocol over TCP/IP networks. iSCSI is a transport layer protocol in the SCSI-3 specifications framework. Other protocols in the transport layer include SCSI Parallel Interface and Fibre Channel.
The iSCSI (pronounced eye-skuzzy) protocol uses TCP/IP for its data transfer. Unlike other network storage protocols, such as Fibre Channel (which is the foundation of most SANs), it requires only the simple and ubiquitous Ethernet interface (or any other TCP/IP-capable network) to operate. This enables low-cost centralization of storage without all of the usual expense and incompatibility normally associated with Fibre Channel storage area networks.

Acceptance of iSCSI in corporate production environments has accelerated now that Gigabit Ethernet is common. Building iSCSI-based Storage Area Networks (SAN) has become a less costly but worthy alternative to creating Fibre Channel-based SANs.

iSCSI terminology and how iSCSI can be used by an OS

An iSCSI initiator, in client/server terminology, is akin to a client device that connects to some service offered by the server (in this case an iSCSI target). An iSCSI target is akin to a server, in that it provides block level access to its storage media (usually a hard drive, but can be other types of SCSI devices if the iSCSI target software supports them.) The primary difference between a regular client/server system and an iSCSI initiator/target system is that while many clients can be simultaneously served by a single server (many-to-one), only one iSCSI initiator can talk to a given iSCSI target at a time (one-to-one).

iSCSI can be used to give an OS block-level access to a remote device (one attached to another computer likely on the same LAN). Depending on the types of devices supported by the iSCSI target, this block-level access can be used to build RAID volumes using remote disks, or to connect and use remote DVD/CD-writers and scanners, or to simply access additional storage space. iSCSI devices are not shared by iSCSI amongst multiple computers at the same time; instead the OS in control of the iSCSI device is responsible for controlling remote access to the device. The initiator and the OS that it is running on will determine how the iSCSI device appears, and whether it is a /dev entry or gets a drive letter or something else.
Source : Weblinkhttp://en.wikipedia.org/wiki/Iscsi


ESG reports that it has identified 2500 iSCSI SAN deployments, and expects deployments to increase substantially in 2005. According to another ESG study of 130 SMB end users, 17% have already deployed an iSCSI SAN, and another 42% are planning to deploy iSCSI SANs by mid 2006. Spectra Logic’s interactions with customers support ESG’s expectations, given the increasing rate of Spectra Logic’s iSCSI products sales, the increasing support of iSCSI drivers/initiators by major operating systems, and the major vendor commitments to the technology.

Microsoft continues to be a major force behind iSCSI, pushing to make iSCSI SAN deployment even easier and even more “risk-free” to the masses. Considering that most of the growth within the storage market will come from small to medium businesses–environments heavily dominated by Windows and Linux–other major storage vendors are certainly enticed to work with MS to make “iSCSI SANs for the masses” a reality. Economics of scale make their decision and direction an easy one, further eased in that iSCSI is already supported in most operating systems.

Source :Weblink from spectralogic.com

A Video Tutorial explaining different Computer Interfaces like PCI,SCSI etc


Video of Kids having fun taking apart a SCSI drive

Where to start if you are preparing for a job in Storage technology

How To Start Planning & Preparing for a Software Job or a Job in Storage (specifically)
Thanks to Triveni Rao one of the blog visitor for contributing this article.

If you want to get a Job in Storage related technology area, prepare on below topics

Fibre Channel networking fundamentals
HBAs (Host Bus Adaptors)
RAID mirroring Backup and Recovery fundamentals
Basic Understanding of File system
Database storage functions
Basic understanding of Storage Virtualization
Loops and Switches (Networking)
How zoning is applied
How LUN masking is applied
Volume management fundamentals
Media management automation
Basic Ethernet/IP networking knowledge
Grip of OS administration(Linux/Solaris preferred)

Start your preparation by knowing all the above mentioned topics theoritically : which means long hours of studying the Big reference books ( Or reading this whole blog as most of these topics are covered on this blog ).
Try to have a practical lab setup where u can configure switches/networks, create & test RAID, Experiment on Volume Management etc.

Once u are good with theory & done several pracitical lab sessions on the above coverable topics - then u start narrowing down on a Job profile which u are interested to work in. It may start with (Job Roles in Storage domain)
- Storage Support
- Storage Field Engineer
- Storage Testing
- Storage documentation
- Storage Planning
- Storage deployment
- Storage interoperability
- Storage Virtualization
- Storage Disaster Recovery
- Storage Migration

Ur role may keep changing but thats how u learn many things in any technology.
Once u are well aware of whats expected of u in a Job Description or Job Profile - you start improving your theoritical as well as practical knowledge in these specific areas.

Once you are confident about the above steps - start attending MOCK INTERVIEWS. If you want I can arrange for a Mock Interview session provided you have prepared well - FREE SERVICE.

Once u have taken enough Mock interviews - start applying for the real company jobs & get some interviews - attend & keep attending interviews. Also dont forget to improve your Domain strengths & reduce the failures in any other related area like - Softskills,HR,PR etc.

KEEP READING & EMAILING ME roger.smithson@gmail.com & I will workwith you to help you succeed & get a High Paying Job in Storage Technology.

Previous Posts on Storage Technology Jobs

Email ur friends about this blog & CC me roger.smithson@gmail.com . I Will send u links of Storage or Tech Job Video with lots of Real Industry Exposure for every friend you email. I want to spread the word & help more people thru this blog .U'll also get many more Surprise Gifts to Boost your Career & Salary.

Storage Area Networking Jobs Interview Questions

EMAIL roger.smithson@gmail.com for FREE EASY to understand SAN Student Guide PDF tutorial

Fibre Channel Network Adapter Card
(Host Bus Adapter- HBA)

Fibre Channel Cable

FC Cable in comparison with a Serial DB9 Cable

After listing more than 60 interview questions in the previous posts find below some listing of only questions from storage interviews. Answers for the same will be sent only through email if you contribute for this blog. Below questions are contributed by Jai one of the professional working in Real Storage Job who contributed this posting.

1)What is the most critical component in SAN?
2)What is the default id for SCSI HBA?
3)What is parallelism?
4)What do you know about SAN testing?
5)Explain a typical SAN landscape?
6)What is fan-in and fan-out in SAN Virtualization system?
7)How is the interoperability between the server and the storage is achieved?
8)What are the performance metrics of SAN?
9)What do you know about I/O meters , their types and how are the used?
10)What is the equivalent of Address resolution protocol in storage?
11)What is meant by availability & reliability in Storage ?
12)What is Disaster Recovery & how it is implemented in a Storage environment?
13)Example for failover cluster configurations ?
14)What are the needs/advantages of Storage consolidation ?

READ BELOW POSTINGS FOR REMAINING 60+ INTERVIEW QUESTIONS WITH ANSWERS ON STORAGE JOBS
PREVIOUS POSTS CAN BE FOUND BY CLICKING THIS LINK

Real Interview Questions contributed by blog reader Jai

Hearty thanks to this blog's reader Jai who has contributed more than 58 interview questions from his experience of attending interviews for real company jobs.

I will be posting these questions in the subsequent blog postings - I rally appreciate his initiative and would request all other professionals or whoever - who have the knowledge to share it with the community and help the jobseekers.

1) What is the difference between RAID 0, RAID 1 and RAID 5?

RAID 0 => Plain striping typically with 24kb, 54kb or 128kb stripe size
RAID 1 => Mirroring
RAID 5 => Stripping with parity

2) Describe in brief the composition of FC Frame?
Start of the Frame locator
Frame header (includes destination id and source id, 24 bytes/6 words)
Data Payload (encapsulate SCSI instruction can be 0-2112 bytes in length)
CRC (error checking, 4 bytes)
End of Frame (1 byte)

3) What is storage virtualization?
Storage virtualization is amalgamation of multiple n/w storage devices into single storage unit.

4) What are the protocols used in physical/datalink and network layer of SAN?
a) Ethernet
b) SCSI
c) Fibre Channel

5) What are the types of disk array used in SAN?
a) JBOD
b) RAID

6) What are different types of protocols used in transportation and session layers of SAN?
a) Fibre Channel Protocol (FCP)
b) Internet SCSI (iSCSI)
c) Fibre Channel IP (FCIP)

7) What is the type of Encoding used in Fibre Channel?
8b/10b, as the encoding technique is able to detect all most all the bit errors

8) How many classes of service are available in Fibre Channel?
7 Classes of service

9) What are the main constrains of SCSI in storage networking?
a) Deployment distance (max. of 25 mts)
b) Number of devices that can be interconnected (16)

10) What is a Fabric?
Interconnection of Fibre Channel Switches

11) What are the services provided by Fabric to all the nodes?
a) Fabric Login
b) SNS
c) Fabric Address Notification
d) Registered state change notification
e) Broadcast Servers

12) What is the difference between LUN and WWN?
LUN: unique number that is assigned to each storage device or partition of the storage that the storage can support.
WWN: 64bit address that is hard coded into a fibre channel HBA and this is used to identify individual port (N_Port or F_Port) in the fabric.

13) What are the different topologies in Fibre Channel?
a) Point-to-Point
b) Arbitrary Loop
c) Switched Fabric Loop

14) What are the layers of Fibre Channel Protocol?
a) FC Physical Media
b) FC Encoder and Decoder
c) FC Framing and Flow control
d) FC Common Services
e) FC Upper Level Protocol Mapping

15) What is zoning?
Fabric management service that can be used to create logical subsets of devices within a SAN. This enables portioning of resources for management and access control purpose.

16) What are the two major classification of zoning?
Two types of zoning are
a) Software Zoning
b) Hardware Zoning

17) What are different levels of zoning?
a) Port Level zoning
b) WWN Level zoning
c) Device Level zoning
d) Protocol Level zoning
e) LUN Level zoning


18) What are the 3 prominent characteristics of SAS Protocol?
a) Native Command Queuing (NCQ)
b) Port Multiplier
c) Port Selector

19) What are the 5 states of Arbitrary Loop in FC?
a) Loop Initialization
b) Loop Monitoring
c) Loop arbitration
d) Open Loop
e) Close Loop

20) How does FC Switch maintain the addresses?
FC Switch uses simple name server to maintain the mapping table