RAID levels

RAID levels

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SCSI, HBA, RAID Questions

1. What is SCSI ? What is SASI
2. What are the advantages of SCSI compared to ATA or IDE ?
3. Explain SCSI ID usage & its usage in narrow SCSI ?
4. Give SCSI Evolution ( Mention different types of SCSI )
5. What is CDB ?
6. What are different SCSI command phases ?
7. Mention device types in SCSI-3 ?
8. What is the difference between LVD & HVD ?
8. What is the difference between SE & Differential (HVD) SCSI ?
9. What is a LUN ?
10.Mention differences between SCS-1,2 and 3 ?
11. What is a terminator ?
12.What are the differences between synchronous & asynchronous SCSI ?
13.What is the default ID of SCSI HBA ?
14.How you will install device drivers for HBA during OS installation ?
15.What is parallel SCSI daisy chaining ?
16.Explain arbitration & Selection process ?
17. What are the maximum no. of devices supported in SCS-1,2 and 3 ?
18. What is the maximum length of cable supported in SCS-1,2 and 3 ?
19. What is the difference between a SCSI HBA & SCSI RAID Controller card ?
20. What is the Disk speed of different SCSI drives ?

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FC questions

Fiber Channel Interview questions from Storage,Network and System administration interview experiences are given here.
1. What is FC ?
2. What are the advantages of FC ?
3. Mention the differences between FC & SCSI ?
4. Explain the layers in FC Protocol ?
5. What are the functions of layer2 and layer3 in FC ?
6. What are different FC topologies ?
7. What is the difference between point to point & Switched in FC ?
8. Explain FC-AL ?
9. Explain the process of initialization in FC ?
10.Explain these terms : LIFA,LIPA,LIHA,LISA
11.What is a Fabric and what are its components ?
12.What are the different FC ports ?
13.Explain different types of flow controls ?
14.What is the difference between buffer to buffer and End to End flow control ?
15.What are the different classes of Services and explain them ?
16.Explain addressing in FC ?
17.Explain FC login process ?
18.What is transmission character and transmission word ?
19.What is a frame, sequence and exchange ?
20.Explain FC frame composition ?
21.Why do we need login in FC ?
22.How many connections are possible in FC ?
23.What are the maximum devices supported in each topologies of FC ?
24.What is the difference between FC & iSCSI ?
25.Mention the FC Controller card manufacturers you know ?

Fibre Channel Controller Card ( Gigabit FC )

FC Layer structure

FC Architecture explained through diagram (another way of representation of Fibre channel layers)

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RAID questions

1. What is RAID?
2. What are the advantages of RAID?
3. What are different levels of RAID?
4. Explain RAID0, RAID1, RAID5 ?
5. Whats the difference between RAID0 & RAID1 ?
6. Whats the difference between RAID1 & RAID5 ?
7. Whats the difference between RAID3 & RAID5 ?
8. Whats the difference between RAID01 & RAID10 ?
9. How many minimum disk drives are needed for R0,R1,R5,R10,R01 ?
10.How RAID 5 works and how parity is calculated ?
11.Other than RAID features what are the other features in Software Management Functionalities ?
12.What is initialization ?
13.What is Check consistency ?
14.What is background verification ?
15.What is a RAID array ?
16.Whats the difference between a JBOD & a RAID array ?
17.When JBOD is preferred over RAID array ?
18.What is a hot spare ?
19.What is a Logical drive or Virtual drive ?
20.What is rebuilding of array ?
21.What you do when a drive in an array fails, how you bring it back to optimal online mode ?
22.What are the different states an array can be in and explain each state?
23.Explain Online,Offline,Degraded states of an array ?
24.What is the difference between a global hotspare & a dedicated hotspare ?
25.How RAID is configured through BIOS ?
26.HoW RAID is configured in OS level?
27.What is the difference between a software RAID & hardware RAID ?
28.Which is best RAID level for performance and which is best for redundancy?

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Fibre channel and storage Questions

1.WHAT ARE THE BENEFITS OF FIBRE CHANNEL SANS?

Fibre Channel SANs are the de facto standard for storage networking in the
corporate data center because they provide exceptional reliability,
scalability, consolidation, and performance. Fibre Channel SANs provide
significant advantages over direct-attached storage through improved
storage utilization, higher data availability, reduced management costs,
and highly scalable capacity and performance.

2.WHAT ENVIRONMENT IS MOST SUITABLE FOR FIBRE CHANNEL SANS?

Typically, Fibre Channel SANs are most suitable for large data centers
running business-critical data, as well as applications that require high-
bandwidth performance such as medical imaging, streaming media, and large
databases. Fibre Channel SAN solutions can easily scale to meet the most
demanding performance and availability requirements.

3.WHAT CUSTOMER PROBLEMS DO FIBRE CHANNEL SANS SOLVE?

The increased performance of Fibre Channel enables a highly effective
backup and recovery approach, including LAN-free and server-free backup
models. The result is a faster, more scalable, and more reliable backup
and recovery solution. By providing flexible connectivity options and
resource sharing, Fibre Channel SANs also greatly reduce the number of
physical devices and disparate systems that must be purchased and managed,
which can dramatically lower capital expenditures. Heterogeneous SAN
management provides a single point of control for all devices on the SAN,
lowering costs and freeing personnel to do other tasks.

4.HOW LONG HAS FIBRE CHANNEL BEEN AROUND?

Development started in 1988, ANSI standard approval occurred in 1994, and
large deployments began in 1998. Fibre Channel is a mature, safe, and
widely deployed solution for high-speed (1Gb, 2Gb, 4Gb) communications and
is the foundation for the majority of SAN installations throughout the
world.

5.WHAT IS THE FUTURE OF FIBRE CHANNEL SANS?

Fibre Channel is a well-established, widely deployed technology with a
proven track record and a very large installed base, particularly in
highperformance, business-critical data center environments. Fibre Channel
SANs continue to grow and will be enhanced for a long time to come.The
reduced costs of Fibre Channel components, the availability of SAN kits,
and the next generation of Fibre Channel (4Gb) are helping to fuel that
growth. In addition, the Fibre Channel roadmap includes plans to double
performance every three years

6.WHAT ARE THE BENEFITS OF 4GB FIBRE CHANNEL?

Benefits include twice the performance with little or no price increase,
investment protection with backward compatibility to 2Gb, higher
reliability due to fewer SAN components (switch and HBA ports) required,
and the ability to replicate, back up, and restore data more quickly. 4Gb
Fibre Channel systems are ideally suited for applications that need to
quickly transfer large amounts of data such as remote replication across a
SAN, streaming video on demand, modeling and rendering, and large
databases. 4Gb technology is shipping today.

7.HOW IS FIBRE CHANNEL DIFFERENT FROM ISCSI?

Fibre Channel and iSCSI each have a distinct place in the IT
infrastructure as SAN alternatives to DAS. Fibre Channel generally
provides high performance and high availability for business-critical
applications, usually in the corporate data center. In contrast, iSCSI is
generally used to provide SANs for business applications in smaller
regional or departmental data centers.

8.WHEN SHOULD I DEPLOY FIBRE CHANNEL INSTEAD OF ISCSI?

For environments consisting of high-end servers that require high
bandwidth or data center environments with business-critical data, Fibre
Channel is a better fit than iSCSI. For environments consisting of many
midrange or low-end servers, an IP SAN solution often delivers the most
appropriate price/performance.

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