clariion interview questions

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Storage Administrator Interview Questions

Author Anilkumar G

Version 1.0

Dated 4March, 2010


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1.WHAT ARE THE BENEFITS OF FIBRE CHANNEL SANS?

Fibre Channel SAs are the de !acto standard !or stora"e net#orkin" in the cor$orate data center because the%$ro&ide e'ce$tional reliabilit%, scalabilit%, consolidation, and $er!ormance. Fibre Channel SAs $ro&idesi"ni!icant ad&anta"es o&er direct(attached stora"e throu"h im$ro&ed stora"e utili)ation, hi"her dataa&ailabilit%, reduced mana"ement costs, and hi"hl% scalable ca$acit% and $er!ormance.

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

*ene!its include t#ice the $er!ormance #ith little or no $rice increase, in&estment $rotection #ith back#ardcom$atibilit% to 2 G*, hi"her reliabilit% due to !e#er SA com$onents +s#itch and *A $orts- reuired, and theabilit% to re$licate, back u$, and restore data more uickl%. 4 G* Fibre Channel s%stems are ideall% suited !ora$$lications that need to uickl% trans!er lar"e amounts o! data such as remote re$lication across a SA,streamin" &ideo on demand, modelin" and renderin", and lar"e databases. 4 G* technolo"% is shi$$in" toda%.

3.HOW IS FIBRE CHANNEL DIFFERENT FROM ISCSI?

Fibre Channel and iSCS/ each ha&e a distinct $lace in the / in!rastructure as SA alternati&es to DAS. FibreChannel "enerall% $ro&ides hi"h $er!ormance and hi"h a&ailabilit% !or business(critical a$$lications, usuall%in the cor$orate data center. /n contrast, iSCS/ is "enerall% used to $ro&ide SAs !or business a$$lications insmaller re"ional or de$artmental data centers.

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

For en&ironments consistin" o! hi"h(end ser&ers that reuire hi"h band#idth or data center en&ironments #ithbusiness(critical data, Fibre Channel is a better !it than iSCS/. For en&ironments consistin" o! man% midran"e orlo#(end ser&ers, an / SA solution o!ten deli&ers the most a$$ro$riate $rice$er!ormance.

5.Name !me !" #$e SAN #!%!&!'(e

oint(to($oint, arbitrated loo$, and s#itched !abric to$olo"ies

).W$a#* #$e +ee, "!- e%a-a#e +e#!-/ "!- #!-a'e $0 LAN a++!# e e,?

3A hard#are and o$eratin" s%stems are "eared to user tra!!ic, and 3As are tuned !or a !ast user res$onse tomessa"in" reuests. ith a SA, the stora"e units can be secured se$aratel% !rom the ser&ers and totall% a$art!rom the user net#ork enhancin" stora"e access in data blocks +bulk data trans!ers-, ad&anta"eous !or ser&er(less backu$s.

.W$a# a-e #$e a,a+#a'e !" RAID?

56edundant Arra% o! /ne'$ensi&e Disks7De$endin" on ho# #e con!i"ure the arra%, #e can ha&e the( data mirrored 86A/D 09 +du$licate co$ies on se$arate dri&es-( stri$ed 86A/D 19 +interlea&ed across se&eral dri&es-, or( $arit% $rotected 86A/D :9+e'tra data #ritten to identi!% errors-.

hese can be used in combination to deli&er the balance o! $er!ormance and reliabilit% that the user reuires.

6.De"(+e RAID? W$($ !+e 0! "ee& ( '!!, $!(e?

6A/D +6edundant arra% o! /nde$endent Disks- is a technolo"% to achie&e redundanc% #ith !aster /;. here areMan% 3e&els o! 6A/D to meet di!!erent needs o! the customer #hich are< 60, 61, 6=, 64, 6:, 610, 6>.Generall% customer chooses 6: to achie&e better redundanc% and s$eed and it is cost e!!ecti&e.


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RAID 1=< >S#-(%%e, M(--!-e,

/n this 6A/D le&el all the data is sa&ed on mirrored &olumes #hich are in turn stri$$ed, so an% disk !ailure sa&esdata loss. he ke% di!!erence !rom 6A/D 01 is that 6A/D 10 creates a stri$ed set !rom a series o! mirroreddri&es. /n a !ailed disk situation 6A/D 10 $er!orms better because all the remainin" disks continue to be used.he arra% can sustain multi$le dri&e losses so lon" as no mirror loses both its dri&es.

his 6A/D le&el is most $re!erred !or hi"h $er!ormance and hi"h data $rotection because rebuildin" o! 6A/D 10is less time consumin" in com$arison to 6A/D 01.

1


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FC C!+#-!&&e-hese are Data trans!er media the% #ill sit on C/ slots o! Ser&erB %ou can con!i"ure Arra%sand &olumes on it.

@BODust *unch o! Disks is Stora"e *o', it consists o! nclosure #here set o! hard(dri&es are hosted in man%combinations such SCS/ dri&es, SAS, FC, SAA.

1).W$($ !+e ( #$e De"a ID "!- SCSI HBA?

Generall% the de!ault /D !or SCS/ *A is H.SCS/( Small Com$uter S%stem /nter!ace*A ( ost *us Ada$tor

1.W$a# ( #$e $('$e# a+, &!e# %-(!-(#0 !" SCSI?

here are 1> di!!erent /DEs #hich can be assi"ned to SCS/ de&ice H, >, :, 4, =, 2, 1, 0, 1:, 14, 1=, 12, 11, 10,I, J.i"hest $riorit% o! SCS/ is /D H and lo#est /D is J.

16.H! ,! 0! (+#a&& ,e(e ,-(e- "!- #$e HBA "(-# #(me ,-(+' OS (+#a&&a#(!+?

/n some scenarios %ou are su$$osed to install ;$eratin" S%stem on the dri&es connected thru SCS/ *A or

SCS/ 6A/D Controllers, but most o! the ;S #ill not be u$dated #ith dri&ers !or those controllers, that time %ouneed to su$$l% dri&ers e'ternall%, i! %ou are installin" #indo#s, %ou need to $ress F> durin" the installation o!;S and $ro&ide the dri&er disk or CD #hich came alon" #ith *A./! %ou are installin" 3inu' %ou need to t%$e Klinu' ddK !or installin" an% dri&er.

1;.Ca+ ,e-(e a#9&ea# 3 #-!&e$!!#(+' e+a-(! $($ 0! $ae !me a-! (+ ,e#a(& ?

SCENARIO 1o# do %ou !inddebu" #hen there is error #hile #orkin" SCS/ de&icesL

/n our dail% SA troubleshootin" there are man% mana"ement and con!i"uration tools #e use them to see #henthere is a !ailure #ith tar"et de&ice or initiator de&ice.Some time it is e&en hard to troubleshoot some o! the thin"s such as media errors in the dri&es, or some o! thedri&es takin" lon" time to s$in(u$. /n such cases these utilities #ill not come to hel$. o debu" this kind o!in!ormation most o! the controller #ill be im$lemented #ith =($in serial debu" $ort. ith serial $ort debu"

connector cable %ou can collect the debu" in!ormation #ith h%$er terminal so!t#are.

SCENARIO 2/ am ha&in" an issue #ith a controller its takin" lot o! time to boot and detect all the dri&esconnected ho# can / sol&e this.L

here are man% $ossibilities that mi"ht cause this $roblem. ;ne o! the reason mi"ht be %ou are usin" baddri&es that cannot be re$aired. /n those cases %ou re$lace the disks #ith #orkin" ones.

Another reason mi"ht be slots %ou connected %our controller to a slot #hich mi"ht not be su$$orted.r% to connect #ith other t%$es o! slots.

;ne more $robable reason is i! %ou ha&e !lashed the !irm#are !or di!!erent ;MEs on the same hard#are.o "et rid o! this the !lash utilities #ill be ha&in" o$tion to erase all the $re&ious and 6;M and boot blockentr% o$tion. @se that o$tion to recti!% the $roblem.

SCENARIO 3/ am usin" ta$e dri&e series H00, e&en the &endor in!ormation on the a$e dri&e sa%s H00,but the ;S in!ormation #hile bootin" the ser&er is sho#in" as :00 #hat could be the $roblemL

First %ou should make sure %our hard#are is o! #hich series, %ou can !ind out this in the $roduct #ebsite.Generall% %ou can see this because in most o! the testin" com$anies the% use same hard#are to test di!!erentseries o! same hard#are t%$e. hat the% do is the% !lash the di!!erent series !irm#are. Nou can al#a%s !lashback to e'act hard#are t%$e.


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2RAID 5 ?

Nou need to ha&e at least = disk dri&es to create 6:.

23.Ca+ 0! +ame !me !" #$e #a#e !" RAID a--a0?

here are states o! 6A/D arra%s that re$resent the status o! the 6A/D arra%s #hich are "i&en belo#a. ;nlineb. De"radedc. 6ebuildin"d. Failed

24.Name #$e "ea#-e !" SCSI93 #a+,a-,?

OAS< Ouick arbitration and selectionDomain ValidationC6C< C%clic redundanc% check

25.Ca+ e a('+ a $!# %a-e #! R< >RAID


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la%er $rotocols to take care o! !rame seuence. he use o! ackno#led"ments reduces a&ailable band#idth,#hich needs to be considered in lar"e(scale bus% net#orks.

C&a93connection less and $ro&ides no noti!ication o! deli&er%here is no dedicated connection in class = and the recei&ed !rames are not ackno#led"ed. Class = is also calleddatagram connectionless ser&ice. /t o$timi)es the use o! !abric resources, but it is no# u$$er la%er $rotocol toensure that all !rames are recei&ed in the $ro$er order, and to reuest to the source de&ice the retransmissiono! missin" !rames. Class = is a commonl% used class o! ser&ice in Fibre Channel net#orks.

C&a94allo#s !ractional band#idth !or &irtual circuitsClass 4 is a connection(oriented ser&ice like class 1, but the main di!!erence is that it allocates onl% a !raction o!a&ailable band#idth o! $ath throu"h the !abric that connects t#o Ports. Virtual Circuits +VCs- are establishedbet#een t#o Ports #ith "uaranteed Oualit% o! Ser&ice +OoS-, includin" band#idth and latenc%. 3ike class 1,class 4 "uarantees in(order deli&er% !rame deli&er% and $ro&ides ackno#led"ment o! deli&ered !rames, but no#the !abric is res$onsible !or multi$le'in" !rames o! di!!erent VCs. Class 4 ser&ice is mainl% intended !ormultimedia a$$lications such as &ideo and !or a$$lications that allocate an established band#idth b%de$artment #ithin the enter$rise. Class 4 #as added in the FC((2 standard.

C&a 95Class : is called isochronous ser&ice, and it is intended !or a$$lications that reuire immediatedeli&er% o! the data as it arri&es, #ith no bu!!erin". /t is not clearl% de!ined %et. /t is not included in the FC(documents.

C&a9)ro&ides multicast, dedicated connection #ith ackno#led"ment

Class > is a &ariant o! class 1, kno#n as multicast class o! ser&ice. /t $ro&ides dedicated connections !or areliable multicast. An Port ma% reuest a class > connection !or one or more destinations. A multicast ser&erin the !abric #ill establish the connections and "et ackno#led"ment !rom the destination $orts, and send it backto the ori"inator. ;nce a connection is established, it should be retained and "uaranteed b% the !abric until theinitiator ends the connection. Class > #as desi"ned !or a$$lications like audio and &ideo reuirin" multicast!unctionalit%. /t a$$ears in the FC((= standard.

C&a9Fused !or s#itch to s#itch communication in the !abric.Class F ser&ice is de!ined in the FC(S and FC(S(2 standard !or use b% s#itches communicatin" throu"h /S3s./t is a connectionless ser&ice #ith noti!ication o! non(deli&er% bet#een Ports used !or control, coordination,and con!i"uration o! the !abric. Class F is similar to class 2B the main di!!erence is that Class 2 deals #ithPorts sendin" data !rames, #hile Class F is used b% P$orts !or control and mana"ement o! the !abric.

3).W$a# a-e #$e ma(+ !+#-a(+ !" SCSI (+ #!-a'e +e#!-/(+'?

a-De$lo%ment distance +ma'. o! 2: mts-b-umber o! de&ices that can be interconnected +1>-

3.W$a# a-e #$e e-(e %-!(,e, 0 Fa-( #! a&& #$e +!,e?

a-Fabric 3o"inb-SSc-Fabric Address oti!icationd-6e"istered state chan"e noti!icatione-*roadcast Ser&ers

36.W$a# ( #$e ,(""e-e+e e#ee+ LUN a+, WWN?

LUNuniue number that is assi"ned to each stora"e de&ice or $artition o! the stora"e that the stora"e cansu$$ort.WWN>4bit address that is hard coded into a !ibre channel *A and this is used to identi!% indi&idual $ort+Port or FPort- in the !abric.

3;.W$a# a-e #$e &a0e- !" F(-e C$a++e& P-!#!!&?

a-FC h%sical Mediab-FC ncoder and Decoderc-FC Framin" and Flo# control


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d-FC Common Ser&icese-FC @$$er 3e&el rotocol Ma$$in"

4


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umber o! eads umber o! C%linders Sectors $er track Sector Si)e

5


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'chan"e is to establish a relationshi$ bet#een 2 P;6s and then these t#o $orts trans!er data &ia one ormore seuence #ithin this relationshi$.'am$le< 'chan"e e'ist to trans!er the command, data and the status o! one SCS/ task

)


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bit character that is assi"ned to the $ort, SA &olume controller uses it to uniuel% identi!% the

!ibre channel *A that is installed in the host s%stem.

3.W$a# ( !++e#(!+ a&&e'(a+e?

Gi&en multi$le connections are established, indi&idual commandres$onse $air must !lo# o&er the sameconnection. his connection alle"iance ensures that s$eci!ic read or #rites commands are !ul!illed #ithout an%additional o&erhead o! monitorin" multi$le connections and to see #hether a $articular reuest is com$leted.

4.W$a# ( -# Le+'#$?

he burst len"th is the number o! b%tes that the SCS/ initiator sends to the SCS/ tar"et in the FCPDAAseuence.

75. How to change clariion SPs IP Address

IMPORTANT: Before you change the IP address of an SP, if the storage system is on a domain, you must removethat storage system from the domain. hen you enter a ne! IP address and acce"t the ac#no!$edgments tochange the address, you !i$$ %e disconnected and the SP !i$$ re%oot. &ou !i$$ then need to $og onto the SP usingthe ne! address and add the storage system to a domain. If the storage system !as the domain Master, !hen youre'connect, you !i$$ need to either recreate the domain and %ecome master or e$se (oin another domain.

)ont forget to create the PPP )ia$u" *onnection %efore attem"ting to $ogin to the SP, other!ise it !i$$ fai$

+. O"en Navis"here Manager.

. If the storage system is in a domain, remove it from the domain.

-. nder the Storage ta%, c$ic# and e/"and the icon for the storage system that you !ant to modify.

0. Right'c$ic# the SP !hose IP address you !ant to change and se$ect Pro"erties.

1. *$ic# the Net!or# ta%.

2. 3nter the ne! IP address in the IP Address f ie$d.

4. *$ic# A""$y to a""$y the change.


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. descri/e various ty0es o% $eta lun

Meta $un can %e created in t!o !ays.

+. Stri"ing: It !i$$ restri"e across %ase $un and ne! $un you added it !i$$ ta#e some time to finish. hi$e in "rogressyou may find some "erformance issues. In this method %ase $un and ne! $un %oth shou$d %e same sie and same

raid grou".

. *oncatenation: it !i$$ a""end the ne! $un to %ase $un. In this method, there is no raid grou", Sie restriction.

1. have changed host na$e ut new host na$e not re%lected in clarion. What the ste0s you are going todo?

2or *icroso%t Windows:

+. sing a te/t editor that does not add s"ecia$ formatting, create a fi$e named agentI).t/t in the directory*:=Program


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+. sing a te/t editor that does not add s"ecia$ formatting, createor edit a fi$e named agentI).t/t in either = 8root9 orin a directory of your choice.. Add the hostname and IP address $ines as descri%ed a%ove. This fi$e shou$d contain on$y these t!o $ines, !ithoutformatting.-. Save the agentI).t/t fi$e.0. If you created the agentI).t/t fi$e in a directory other than root, for Navis"here Agent to restart after a systemre%oot using the correct "ath to the agentI).t/t fi$e, set the environment varia%$e 3?@A73NTI)@)IR3*TOR& to

"oint to the directory !here you created agentI).t/t.1. If a 5ostId


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Po!er Su""$iesD Turn on A* Po!er to SP3Po!er Su""$yE Po!er is not actua$$y a""$ied

D Turn on A* "o!er to SPSEA* Po!er !i$$ %e a""$ied toSP3E Battery %ac#u" !i$$ start

chargingD Po!er on attached hostsE


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#5. What is the di%%erence /etween navis0here classic "!I and Secure "!I


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#6. Why do we de%rag$ent raid grou0s

RAI) 7rou" defragmented means that a$$ 6Ns on the RAI) grou" !i$$ %e made contiguous, there%yremoving any unused s"ace %et!een 6Ns. It is im"ortant to note that defragmentation does not defragment fi$eson the 6Ns D the storage system is not a!are of the fi$esystem structure used on any host 6Ns.


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Access $ogic is $icensed soft!are %y using this you can do 6N Mas#ing.

D *ontro$s !hich host have access to !hich 6NsDA$$o!s mu$ti"$e hosts to effective$y share a *6ARiiON array !ithout the ris# of data corru"tionD 5osts sharing "orts can run the same or different o"erating systemsD The *6ARiiON administrator contro$s !hich hosts access !hich 6Ns %y assigning the host and 6Ns to aStorage 7rou"

)&). "lariion !i$itations with res0ect to nu$/er o% !uns, aid grou0s, storage grou0 and nu$/er hosts0er connected to storage grou0, nu$er o% initiators %or storage syste$.

)&. A%ter creating *eta !un how do you e0and the lun si+e at host side in windows

indo!s : Run )is#"ar command

)&1. What is ;*" 0ower 0ath why it is used in clarion s0ace.

)&8. ;0lain a/out ;*" load /alancing algorith$s

D *$arO"t: I=O reCuests are %a$anced across mu$ti"$e "aths %ased on com"osition of reads, !rites, "$us userassigna%$e "riority

D 6eastIOs: I=O reCuests are assigned to the "ath !ith the fe!est num%er of reCuests in the Cueue

D 6eastB$oc#s: I=O reCuests are assigned to the "ath !ith the fe!est tota$ %$oc#s in the Cueue

D RoundRo%in: I=O reCuests are distri%uted to each avai$a%$e "ath in rotation

D ReCuest: No 6oad %a$ancing %ut !i$$ "erform "ath fai$over as reCuired

D Basic


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:J nav$ci Dh SPB managefi$es D$ist:J navi$ci Dh SPA mangefi$es Dretrive:J navic$i Dh SPB managefi$es Dretrive

))1. "lariion


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