NetApp Interview Q & A
1. What is QTree..?
Ans: - A qtree is different from the traditional
directory on a UNIX system in many ways including
1. A qtree can be assigned a security style. We can
create a qtree with UNIX, NT or mixed security style.
2. CIFS oplocks can be enabled on the qtree. CIFS oplocks
help the client to buffer data locally, performing read ahead from an open
file. The nature of buffering depends on the nature of oplocks granted.
3. We can set disk space & file limits at qtree
level, allowing control over resource allocation to multiple projects.
Say we have 3 departments, finance, HR, sales and each
function has separate qtree's. We can then assign 20 GB to sales, 100 GB to HR,
since it contains training videos etc. and 75 GB to finance.
Ans: -
1. Traditional
2. Flexvol
Volume important stuff:
The name of the volume
◆
The size of the volume
◆
A security style, which determines whether a volume can contain files that use UNIX security,
files that use NT file system (NTFS) file security, or both types of files
◆
Whether the volume uses CIFS oplocks (opportunistic locks)
◆
The type of language supported
◆
The level of space guarantees (for FlexVol volumes only)
◆
Disk space and file limits (quotas)
◆
A snapshot schedule
◆
Whether the volume is designated as a SnapLock™
volume
◆
Whether the volume is a root.
Traditional volume
The smallest possible 2 disk raid4 3 disk raiddp
A traditional volume is contained by a single, dedicated,
aggregate.
The only way to increase the size of a traditional volume
is to add entire disks to
its containing aggregate
it is impossible to decrease the size of a traditional
volume.
Flexible volume (FlexVol):
Because the volume is managed separately from the
aggregate,
FlexVol volumes give you a lot more options for managing
the size of the
volume.
You can create FlexVol volumes in an aggregate nearly
instantaneously.
They can be as small as 20 MB and as large as the volume
capacity that is
supported for your storage system
You can increase and decrease the size of a FlexVol in
small increments (as
small as 4 KB), nearly instantaneously
3. Difference between Volume Snap Mirror and Qtree Snap Mirror..?
Ans:-
Volume SnapMirror
|
Qtree SnapMirror
|
Synchronous or
asynchronous replication is supported for volumes.
|
Only asynchronous
replication is supported for qtrees.
|
Destination volume
is read-only.
|
Destination qtree
is read-only. However, the volume on which the qtree is located must be
online and writable.
|
Source and
destination volumes must both be either traditional volumes
or FlexVol volumes.
|
Source and
destination qtrees can be on any type of volumes, traditional volumes
or FlexVol volumes.
|
Replicates Snapshot
copies of a source volume and all its qtrees, to the destination volume
|
Replicates only the
contents of an individual qtree to a destination
|
You need to set a
destination volume to restricted, read-only status, before setting it up for
replication.
|
The destination
volume for qtree replication is writable, and must not be read-only.
|
Replication of a
volume on the destination takes up the space allocated to the source volume,
irrespective of how much of the volume is used for storing data.
|
If you need to
mirror only the data stored on an individual qtree, then SnapMirror
replication of that individual qtree uses slightly more disk space and
directories on the destination qtree than the source qtree.
|
Replication can be
set up to a destination volume from only one source volume. This implies that
one destination volume cannot be used for replicating multiple source
volumes.
|
Replication can be
set up for a maximum of 255 qtrees on any one volume.
|
Block-for-block
replication
It transfers the file system
verbatim. Therefore, older releases of Data ONTAP cannot understand
file system transfers from a later release of Data ONTAP.
|
Logical replication
All the files and directories in the
source file system are created in the destination file system. Therefore, you
can replicate data between astorage system running an older version
of Data ONTAP and a storage system running a newer
version.
Note: If the source file system contains a file type that cannot
be represented on the destination file system, the replication will fail. For
example, Data ONTAP 7.0 supports files up to 16 TB in size, whereas
earlier versions of Data ONTAP support files up to 4 TB. If the
source system is running Data ONTAP 7.0, the qtree you want to
replicate contains a file greater than 4 TB, and the destination system is
running an earlier version of Data ONTAP, the replication will fail.
|
4. Difference between Hard Zoning and Soft Zoning..?
Ans:- Here's what I thought
was correct:
·
Hard zoning is done by
the switches, disallowing certain WWNs (or ports) from talking by examining
source and destination information, regardless of knowledge of one another's
existence. I compare this to conventional IP firewalls (only certain IPs can
talk to one another - I know Google's IP but I still cannot reach it).
·
Soft zoning allows everything
to reach everything else, but prevents discovery of everything in the fabric by
limiting what information the name server will respond with when a new HBA
wants to know what it can talk to. I compare this to a DNS server that provides
different responses based on the querying host - hosts can still talk if they
know one another's IP address.
·
WWN and port-based
zoning are unrelated to the above - they simply imply how you identify members
of a zone.
Ans:- Aggr
status -v
(Optional) Determine the free disk resources on your filer by entering
the following command:
aggr status -s
3 To create a traditional volume, enter the following command:
aggr create trad_vol -v ndisks[@disksize]
Example:
aggr create new_tvol -v 16@72g
4 (Optional) To verify the creation of the traditional volume named
new_tvol, enter the following command:
vol status new_tvol -v 16@72g
All volumes, including traditional volumes, must be uniquely
named within the same filer.
◆ you can create a maximum of 100 traditional volumes within
one storage system.
◆ Minimum traditional volume size depends on the disk capacity
and RAID protection level
(Optional) Determine the free disk resources on your filer by entering
the following command:
aggr status -s
3 To create a traditional volume, enter the following command:
aggr create trad_vol -v ndisks[@disksize]
Example:
aggr create new_tvol -v 16@72g
4 (Optional) To verify the creation of the traditional volume named
new_tvol, enter the following command:
vol status new_tvol -v 16@72g
All volumes, including traditional volumes, must be uniquely
named within the same filer.
◆ you can create a maximum of 100 traditional volumes within
one storage system.
◆ Minimum traditional volume size depends on the disk capacity
and RAID protection level
Ans:-
Port
|
Full Name
|
Port Function
|
N-port
|
network port or node port
|
Node port used to connect a node to a Fibre Channel switch
|
F-port
|
fabric port
|
Switch port used to connect the Fibre Channel fabric to a node
|
L-port
|
loop port
|
Node port used to connect a node to a Fibre Channel loop
|
NL-port
|
network + loop port
|
Node port which connects to both loops and switches
|
FL-port
|
fabric + loop port
|
Switch port which connects to both loops and switches
|
E-port
|
extender port
|
Used to cascade Fibre Channel switches together
|
G-port
|
general port
|
General purpose port which can be configured to emulate other
port types
|
EX_port
|
external port
|
Connection between a fibre channel router and a fibre channel
switch; on the switch side, it looks like a normal E_port -- but on the
router side, it is a EX_port
|
TE_port
|
trunking E-port
|
Povides standard E_port functions and allows for routing of
multiple virtual SANs by modifying the standard Fibre Channel frame upon
ingress/egress of the VSAN environment
|
Ans:- A storage area network (SAN) is a high-speed
special-purpose network (or subnetwork) that interconnects different kinds of
data storage devices with associated data servers on behalf of a larger network
of users. Typically, a storage area network is part of the overall network of
computing resources for an enterprise. A storage area network is usually
clustered in close proximity to other computing resources such as IBM Power5
boxes but may also extend to remote locations for backup and archival storage, using
wide area network carrier technologies such as ATM or SONET .
A storage area network can use existing communication
technology such as IBM’s optical fiber ESCON or it may use the newer Fibre
Channel technology. Some SAN system integrators liken it to the common storage
bus (flow of data) in a personal computer that is shared by different kinds of
storage devices such as a hard disk or a CD-ROM player.
SANs support disk mirroring, backup and restore, archival
and retrieval of archived data, data migration from one storage device to
another, and the sharing of data among different servers in a network. SANs can
incorporate subnetworks with network-attached storage (NAS) systems.
Ans:- Network-attached storage (NAS) is hard disk storage that
is set up with its own network address rather than being attached to the
department computer that is serving applications to a network’s workstation
users. By removing storage access and its management from the department
server, both application programming and files can be served faster because
they are not competing for the same processor resources. The network-attached
storage device is attached to a local area network (typically, an Ethernet
network) and assigned an IP address. File requests are mapped by the main
server to the NAS file server.
Network-attached storage consists of hard disk storage,
including multi-disk RAID systems, and software for configuring and mapping
file locations to the network-attached device. Network-attached storage can be
a step toward and included as part of a more sophisticated storage system known
as a storage area network (SAN).
NAS software can usually handle a number of network
protocols, including Microsoft’s Internetwork Packet Exchange and NetBEUI,
Novell’s Netware Internetwork Packet Exchange, and Sun Microsystems’ Network
File System. Configuration, including the setting of user access priorities, is
usually possible using a Web browser.
Ans:- SMTP (Simple Mail Transfer Protocol) is a TCP/IP protocol
used in sending and receiving e-mail. However, since it is limited in its
ability to queue messages at the receiving end, it is usually used with one of
two other protocols, POP3 or IMAP, that let the user save messages in a server
mailbox and download them periodically from the server. In other words, users
typically use a program that uses SMTP for sending e-mail and either POP3 or
IMAP for receiving e-mail. On Unix-based systems, sendmail is the most
widely-used SMTP server for e-mail. A commercial package, Sendmail, includes a
POP3 server. Microsoft Exchange includes an SMTP server and can also be set up
to include POP3 support.
SMTP usually is
implemented to operate over Internet port 25.
Ans:- Short for Network Address Translation, an Internet
standard that enables a local-area network (LAN) to use one set of IP addresses
for internal traffic and a second set of addresses for external traffic. A NAT
box located where the LAN meets the Internet makes all necessary IP address
translations.
NAT serves three main purposes:
Provides a type of firewall by hiding internal IP
addresses
Enables a company to use more internal IP addresses.
Since they’re used internally only, there’s no possibility of conflict with IP
addresses used by other companies and organizations.
Allows a company to combine multiple ISDN connections
into a single Internet connection.
Explain DHCP and its uses to an environment?
Short for Dynamic Host Configuration Protocol, a protocol
for assigning dynamic IP addresses to devices on a network. With dynamic
addressing, a device can have a different IP address every time it connects to
the network. In some systems, the device’s IP address can even change while it
is still connected. DHCP also supports a mix of static and dynamic IP
addresses.
Dynamic addressing simplifies network administration
because the software keeps track of IP addresses rather than requiring an
administrator to manage the task. This means that a new computer can be added
to a network without the hassle of manually assigning it a unique IP address.
Many ISPs use dynamic IP addressing for dial-up users.
Ans:- Short for Simple Network Management Protocol, a set of
protocols for managing complex networks. SNMP works by sending messages, called
Protocol Data Units, to different parts of a network. SNMP-compliant devices,
called Agents, store data about themselves in Management Information Bases and
return this data to the SNMP requesters.
Ans:- TCPdump is a common computer network debugging tool that
runs under the command line. It allows the user to intercept and display TCP/IP
and other packets being transmitted or received over a network to which the
computer is attached. Tcpdump works on most Unix-like platforms: Linux,
Solaris, BSD, Mac OS X, HP-UX and AIX among others. On Windows, WinDump can be
used; it’s a port of tcpdump to Windows.
You must have a root or super user authority to use
TCPdumps in UNIX like envrionment.
Ans:- Redundant Arrays of Independent Disks (RAID) is formally
defined as a method to store data on any type of disk medium.
LDAP
The Light Directory Access Protocol (LDAP) defines a
standard method for accessing and updating information in a directory (a
database) either locally or remotely in a client-server model.
Ans:- 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.
Ans:- 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.
Ans:- 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.
Ans:- 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 (1 GB, 2 GB, 4 GB)
communications and is the foundation for the majority of SAN installations
throughout the world.
Ans:- Fibre Channel is a well-established, widely deployed
technology with a proven track record and a very large installed base,
particularly in high-performance, 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 (4 GB) are helping to fuel that
growth. In addition, the Fibre Channel roadmap includes plans to double
performance every three years.
Ans:- Benefits include twice the performance with little or no
price increase, investment protection with backward compatibility to 2 GB,
higher reliability due to fewer SAN components (switch and HBA ports) required,
and the ability to replicate, back up, and restore data more quickly. 4 GB
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. 4 GB
technology is shipping today.
Ans:- 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.
Ans:- 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.
Ans: - Point-to-point, arbitrated loop, and switched fabric
topologies.
What’s the need for separate network for storage why LAN
cannot be used?
LAN hardware and operating systems are geared to user
traffic, and LANs are tuned for a fast user response to messaging requests.
With a SAN, the storage units can be secured separately
from the servers and totally apart from the user network enhancing storage
access in data blocks (bulk data transfers), advantageous for server-less
backups.
Ans:- “Redundant Array of Inexpensive Disks”
Depending on how we configure the array, we can have the
- data mirrored [RAID 1] (duplicate copies on separate drives)
- striped [RAID 0] (interleaved across several drives),
or
- parity protected [RAID 5](extra data written to
identify errors).
These can be used in combination to deliver the balance
of performance and reliability that the user requires.
Ans: - RAID (Redundant array of Independent Disks) is a
technology to achieve redundancy with faster I/O. There are Many Levels of RAID
to meet different needs of the customer which are: R0, R1, R3, R4, R5, R10, R6.
Generally customer chooses R5 to achieve better
redundancy and speed and it is cost effective.
R0 – Striped set without parity/[Non-Redundant Array].
Provides improved performance and additional storage but
no fault tolerance. Any disk failure destroys the array, which becomes more
likely with more disks in the array. A single disk failure destroys the entire
array because when data is written to a RAID 0 drive, the data is broken into
fragments. The number of fragments is dictated by the number of disks in the
drive. The fragments are written to their respective disks simultaneously on
the same sector. This allows smaller sections of the entire chunk of data to be
read off the drive in parallel, giving this type of arrangement huge bandwidth.
RAID 0 does not implement error checking so any error is unrecoverable. More
disks in the array means higher bandwidth, but greater risk of data loss
R1 – Mirrored set without parity.
Provides fault tolerance from disk errors and failure of
all but one of the drives. Increased read performance occurs when using a
multi-threaded operating system that supports split seeks, very small
performance reduction when writing. Array continues to operate so long as at
least one drive is functioning. Using RAID 1 with a separate controller for
each disk is sometimes called duplexing.
R3 – Striped set with dedicated parity/Bit interleaved
parity.
This mechanism provides an improved performance and fault
tolerance similar to RAID 5, but with a dedicated parity disk rather than
rotated parity stripes. The single parity disk is a bottle-neck for writing
since every write requires updating the parity data. One minor benefit is the
dedicated parity disk allows the parity drive to fail and operation will
continue without parity or performance penalty.
R4 – Block level parity.
Identical to RAID 3, but does block-level striping
instead of byte-level striping. In this setup, files can be distributed between
multiple disks. Each disk operates independently which allows I/O requests to
be performed in parallel, though data transfer speeds can suffer due to the
type of parity. The error detection is achieved through dedicated parity and is
stored in a separate, single disk unit.
R5 – Striped set with distributed parity.
Distributed parity requires all drives but one to be
present to operate; drive failure requires replacement, but the array is not
destroyed by a single drive failure. Upon drive failure, any subsequent reads
can be calculated from the distributed parity such that the drive failure is
masked from the end user. The array will have data loss in the event of a
second drive failure and is vulnerable until the data that was on the failed
drive is rebuilt onto a replacement drive.
R6 – Striped set with dual distributed Parity.
Provides fault tolerance from two drive failures; array
continues to operate with up to two failed drives. This makes larger RAID
groups more practical, especially for high availability systems. This becomes
increasingly important because large-capacity drives lengthen the time needed
to recover from the failure of a single drive. Single parity RAID levels are
vulnerable to data loss until the failed drive is rebuilt: the larger the
drive, the longer the rebuild will take. Dual parity gives time to rebuild the
array without the data being at risk if one drive, but no more, fails before
the rebuild is complete.
Ans:- RAID 0+1 (Mirrored Stripped)
In this RAID level all the data is saved on stripped
volumes which are in turn mirrored, so any disk failure saves the data loss but
it makes whole stripe unavailable. The key difference from RAID 1+0 is that
RAID 0+1 creates a second striped set to mirror a primary striped set. The
array continues to operate with one or more drives failed in the same mirror
set, but if drives fail on both sides of the mirror the data on the RAID system
is lost. In this RAID level if one disk is failed full mirror is marked as
inactive and data is saved only one stripped volume.
RAID 1+0 (Stripped Mirrored)
In this RAID level all the data is saved on mirrored
volumes which are in turn stripped, so any disk failure saves data loss. The
key difference from RAID 0+1 is that RAID 1+0 creates a striped set from a
series of mirrored drives. In a failed disk situation RAID 1+0 performs better
because all the remaining disks continue to be used. The array can sustain
multiple drive losses so long as no mirror loses both its drives.
This RAID level is most preferred for high performance
and high data protection because rebuilding of RAID 1+0 is less time consuming
in comparison to RAID 0+1.
Ans:- “Just a Bunch of Disks”
It is a collection of disks that share a common
connection to the server, but don’t include the mirroring,
striping, or parity facilities that RAID systems do, but
these capabilities are available with host-based software.
Ans:- RAID: “Redundant Array of Inexpensive Disks”
Fault-tolerant grouping of disks that server sees as a
single disk volume
Combination of parity-checking, mirroring, striping
Self-contained, manageable unit of storage
JBOD: “Just a Bunch of Disks”
Drives independently attached to the I/O channel
Scalable, but requires server to manage multiple volumes
Do not provide protection in case of drive failure
Ans:- Host bus adapters (HBAs) are needed to connect the server
(host) to the storage.
Ans:- Massively extended scalability.
Greatly enhanced device connectivity.
Storage consolidation.
LAN-free backup.
Server-less (active-fabric) backup.
Server clustering.
Heterogeneous data sharing.
Disaster recovery – Remote mirroring.
While answering people do NOT portray clearly what they
mean & what advantages each of them have, which are cost effective &
which are to be used for the client’s requirements.
Ans: - he basic difference between SAN and NAS, SAN is Fabric
based and NAS is Ethernet based.
SAN – Storage Area Network
It accesses data on block level and produces space to
host in form of disk.
NAS – Network attached Storage
It accesses data on file level and produces space to host
in form of shared network folder.
What is a typical storage area network consists of – if
we consider it for implementation in a small business setup?
If we consider any small business following are
essentials components of SAN:
Fabric Switch.
FC Controllers.
JBOD’s.
Ans:- Fabric Switch: It’s a device which interconnects multiple
network devices .There are switches starting from 16 port to 32 ports which
connect 16 or 32 machine nodes etc. vendors who manufacture these kind of
switches are Brocade, McData.
Ans:- Each component has its own criticality with respect to
business needs of a company.
Ans:- There are many management software’s used for managing
SAN’s to name a few:
Santricity.
IBM Tivoli Storage Manager.
CA Unicenter.
Veritas Volumemanger.
Which one is the Default ID for SCSI HBA?
Generally the default ID for SCSI HBA is 7.
SCSI- Small Computer System Interface.
HBA – Host Bus Adaptor.
Ans:- There are 16 different ID’s which can be assigned to SCSI
device 7, 6, 5, 4, 3, 2, 1, 0, 15, 14, 13, 12, 11, 10, 9, 8.
Highest priority of SCSI is ID 7 and lowest ID is 8.
How do you install device drivers for the HBA first time
during OS installation?
In some scenarios you are supposed to install Operating
System on the drives connected thru SCSI HBA or SCSI RAID Controllers, but most
of the OS will not be updated with drivers for those controllers, that time you
need to supply drivers externally, if you are installing windows, you need to
press F6 during the installation of OS and provide the driver disk or CD which
came along with HBA.
If you are installing Linux you need to type “linux dd”
for installing any driver.
Ans:- Array is a group of Independent physical disks to
configure any Volumes or RAID volumes.
36A. SCENARIO 1: How do you find/debug when there is
error while working SCSI devices?
In our daily SAN troubleshooting there are many
management and configuration tools we use them to see when there is a failure
with target device or initiator device.
Some time it is even hard to troubleshoot some of the
things such as media errors in the drives, or some of the drives taking long
time to spin-up. In such cases these utilities will not come to help. To debug
this kind of information most of the controller will be implemented with 3-pin
serial debug port. With serial port debug connector cable you can collect the
debug information with hyper terminal software.
36B. SCENARIO 2: I
am having an issue with a controller its taking lot of time to boot and detect
all the drives connected how can I solve this.?
There are many possibilities that might cause this problem.
One of the reason might be you are using bad drives that cannot be repaired. In
those cases you replace the disks with working ones.
Another reason might be slots you connected your
controller to a slot which might not be supported.
Try to connect with other types of slots.
One more probable reason is if you have flashed the
firmware for different OEM’s on the same hardware.
To get rid of this the flash utilities will be having
option to erase all the previous and EEPROM and boot block entry option. Use
that option to rectify the problem.
36C. SCENARIO 3: I
am using tape drive series 700X, even the vendor information on the Tape drive
says 700X, but the POST information while booting the server is showing as 500X
what could be the problem?
First you should make sure your hardware is of which
series, you can find out this in the product website.
Generally you can see this because in most of the testing
companies they use same hardware to test different series of same hardware
type. What they do is they flash the different series firmware. You can always
flash back to exact hardware type.
Ans:- Core-edge.
Full-Mesh.
Partial-Mesh.
Cascade.
Ans:- dmesg
Ans:- You need to have at least 3 disk drives to create R5.
Ans:- There are states of RAID arrays that represent the status
of the RAID arrays which are given below:
Online.
Degraded.
Rebuilding.
Failed.
Ans:- Ethernet.
SCSI.
Fibre Channel.
Ans:- Storage virtualization is amalgamation of multiple n/w
storage devices into single storage unit.
Ans:- 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).
Ans:- Virtualization is logical representation of physical
devices. It is the technique of managing and presenting storage devices and
resources functionally, regardless of their physical layout or location.
Virtualization is the pooling of physical storage from multiple network storage
devices into what appears to be a single storage device that is managed from a
central console. Storage virtualization is commonly used in a storage area
network (SAN). The management of storage devices can be tedious and
time-consuming. Storage virtualization helps the storage administrator perform
the tasks of backup, archiving, and recovery more easily, and in less time, by
disguising the actual complexity of the SAN.
Ans:- HA High Availability is a technology to achieve failover
with very less latency. Its a practical requirement of data centers these days
when customers expect the servers to be running 24 hours on all 7 days around
the whole 365 days a year – usually referred as 24x7x365. So to achieve this, a
redundant infrastructure is created to make sure if one database server or if
one app server fails there is a replica Database or Appserver ready to
take-over the operations. End customer never experiences any outage when there
is a HA network infrastructure.
Ans:- There are many types of tape media available to back up
the data, some of them are:
DLT: Digital Linear Tape – technology for tape
backup/archive of networks and servers; DLT technology addresses midrange to
high-end tape backup requirements.
LTO: Linear Tape Open; a new standard tape format
developed by HP, IBM, and Seagate.
AIT: Advanced Intelligent Tape; a helical scan technology
developed by Sony for tape backup/archive of networks and servers, specifically
addressing midrange to high-end backup requirements.
Ans:- No, since R0 is not redundant array, failure of any disks
results in failure of the entire array so we cannot rebuild the hot spare for
the R0 array.
Ans:- QAS: Quick arbitration and selection.
Domain Validation.
CRC: Cyclic redundancy check.
Ans:- Fault tolerant technique where, there is more than one
physical path between the CPU in the computer systems and its main storage
devices through the buses, controllers, switches and other bridge devices
connecting them.
Ans:- Set of high performance storage disks that can store
several terabytes of data. Single disk array can support multiple points of
connection to the network.
Ans:- Fibre Channel Protocol (FCP).
Internet SCSI (iSCSI).
Fibre Channel IP (FCIP).
Ans:- 8b/10b, as the encoding technique is able to detect all
most all the bit errors
Ans:- Deployment distance (max. of 25 mts).
Number of devices that can be interconnected (16).
Ans:- Interconnection of Fibre Channel Switches.
Ans:- Fabric Login.
SNS
Fabric Address
Notification.
Registered state change notification.
Broadcast Servers.
56. What is the difference between LUN and WWN?
Ans:- 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.
Ans:- Point-to-Point.
Arbitrary Loop.
Switched Fabric Loop.
58. What are the layers of Fibre Channel Protocol?
Ans:- FC Physical Media.
FC Encoder and Decoder.
FC Framing and Flow control.
FC Common Services.
FC Upper Level Protocol Mapping.
59. What is zoning?
Ans:- 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.
Ans:- Probability of unavailability of data stored on the disk
array due to single point failure is totally eliminated.
Ans:- FC Switch uses simple name server (SNS) to maintain the
mapping table.
Ans:- Two types of zoning are:
Software Zoning.
Hardware Zoning.
63. What are different levels of zoning?
Ans:- Port Level zoning.
WWN Level zoning.
Device Level zoning.
Protocol Level zoning.
LUN Level zoning.
64. What are the 3 prominent characteristics of
SAS Protocol?
Ans:- Native Command Queuing (NCQ.)
Port Multiplier.
Port Selector.
65. What are the 5 states of Arbitrary Loop in
FC?
Ans:- Loop Initialization.
Loop Monitoring.
Loop arbitration.
Open Loop.
Close Loop.
66. What is LUN Masking?
Ans:- A method used to create an exclusive storage area and
access control. And this can be achieved by storage device control program.
Ans:- A snapshot of data object contains an image of data at a
particular point of time.
Ans:- Devices are allowed to be removed and inserted into a
system without turning off the system.
good one!!
ReplyDeleteUseful.. Thanks a lot
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