SAN FAQs
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1) What is the differerence b/w SAN and NAS ? The basic difference between SAN and NAS , SAN is Fabric based and NAS is Ethernet based. SAN - Storage Area Network NAS - Network attached Storage )What is a t!"ica# storage area network consists of - if we consider it for i$"#e$entation in a s$a## b%siness set%" ? &f we consider an! s$a## b%isenss fo##owing are essentia#s co$"onets of SAN - Fabric Switch - F' 'ontro##ers - ()*+,s -)'an !o% brief#! e."#ain each of these Storage area co$"onents? Fabric Swictch/ &t,s a de0ice which interconnects $%#ti"#e network de0ices .There are swithes starting fro$ 11 "ort to - "orts which connect 11 or $achine nodes etc.2endors who $an%fact%re these kind of switches are )rocade, 3c+ata. F' 'ontro##ers / These are +ata transfer $edias the! wi## sit on 4'& s#ots of Ser0er,% can config%re Arra!s and 0o#%$es on it. ()*+/ (%st )%nch of +isks is Storage )o.,it consists of Enc#os%re where set of harddri0es are hosted in $an! co$binations s%ch S'S& dri0es,SAS ,F',SATA. 5)What is the $ost critica# co$"onent in SAN ? Each co$"onent has its own critica#it! with res"ect to b%isness needs of a co$"an!. 6) +efine 7A&+ ? Which one !o% fee# is good choice ? 7A&+ 87ed%ndant arra! of &nde"endent +isks) is a techno#og! to achi0e red%ndanc! with faster &/*.There are 3an! 9e0e#s of 7A&+ to $eet different needs of the c%sto$er which are / 7:,71,76,71:,76. ;enera##! c%sto$er choose 76 to achi0e better red%ndanc! and s"eed and it is cost effecti0e. 1)<ow is a SAN $anaged ? There are $an! $anage$ent softwares %sed for $anaging SAN,s to na$e a few Santricit! &)3 Ti0o#i Storage 3anager. 'A =nicenter. 2eritas 2o#%$e$anger.
>) Which one is the +efa%#t &+ for S'S& <)A ? ;enera##! the defa%#t &+ for S'S& <)A is >. S'S&- S$a## 'o$"%ter S!ste$ &nterface
<)A - <ost )%s Ada"tor ?) <ow do !o% insta## de0ice dri0ers for the <)A first ti$e d%ring *S insta##ation ? &n so$e scenarios !o% are s%""osed to insta## *"erating S!ste$ on the dri0es connected thr% S'S& <)A or S'S& 7A&+ 'onro##ers,b%t $ost of the *S,es wi## not be %"dated with dri0ers for those contro##ers,that ti$e !o% need to s%""#! dri0ers e.terna##!,if !o% are insta##ing windows ,!o% need to "ress F1 d%ring the insta##ion of *S and "ro0ide the dri0er disk or '+ which ca$e a#ong with <)A. &f !o% are insta##ing #in%. !o% need to t!"e @#in%. dd@ for insta##ing an! dri0er. A) What is Arra! ? Arra! is a gro%" of &nde"endent "h!sica# disks to config%re an! 2o#%$es or 7A&+ 0o#%$es. 1:)'an % describe at#east - tro%b#eshooting scenarios which !o% ha0e co$e across in detai# ? S'ENA7&* 1/<ow do !o% find/deb%g when there is error whi#e working S'S& de0ices? &n o%r dai#! SAN tro%b#eshooting there are $an! $anage$ent and config%ration too#s we %se the$ to see when there is a fai#%re with target de0ice or initiator de0ice. So$e ti$e it is e0en hard to tro%b#e shoot so$e of the things s%ch as $edia errors in the dri0es, or so$e of the dri0es taking #ong ti$e to s"inn%".&n s%ch cases these %ti#ities wi## not co$e to he#".To deb%g this kind of infor$ation $ost of the contro##er wi## be i$"#e$ented with --"in seria# deb%g "ort. With seria# "ort deb%g connector cab#e !o% can co##ect the deb%g infor$ation with h!"er ter$ina# software. S'ENA7&* / & a$ ha0ing an iss%e with a contro##er its taking #ot of ti$e to boot and detect a## the dri0es connected how can & so#0e this.? There are $an! "ossibi#ities that $ight ca%se this "rob#e$. *ne of the reason $ight be !o% are %sing bad dri0es that cannot be re"aired . &n those cases !o% re"#ace the disks with working ones. Another reason $ight be s#ots !o% connected !o%r contro##er to a s#ot which $ight not be s%""orted. Tr! to connect with other t!"es of s#ots. *ne $ore "robab#e reason is if !o% ha0e f#ashed the fir$ware for different *E3Bs on the sa$e hardware. To get rid of this the f#ash %ti#ities wi## be ha0ing o"tion to erase a## the "re0io%s and EE47*3 and boot b#ock entr! o"tion. =se that o"tion to rectif! the "rob#e$. S'ENA7&* -/ & a$ %sing ta"e dri0e series >::C , e0en the 0endor infor$ation
on the Ta"e dri0e sa!s >::C, b%t the 4*ST infor$ation whi#e booting the ser0er is showing as 6::C what co%#d be the "rob#e$? First !o% sho%#d $ake s%re !o%r hardware is of which series , !o% can find o%t this in the "rod%ct website. ;enera##! !o% can see this beca%se in $ost of the testing co$"anies the! %se sa$e hardware to test different series of sa$e hardware t!"e. What the! do is the! f#ash the different series fir$ware. Do% can a#wa!s f#ash back to e.act hardware t!"e. 11.Which are the SAN to"o#ogies? Answer /SAN can be connected in - t!"es which are $entioned be#ow/ 4oint to 4oint to"o#og! F' Arbitrated 9oo" 8 F' /Fibre 'hanne# ) Switched Fabric 1 ) Which are the 5 t!"es of SAN architect%re t!"es Answer /'ore-edge F%##-3esh 4artia#-3esh 'ascade 1-) which co$$and is %sed in #in%. to know the dri0er 0ersion of an! hardware de0ice ? Answer / d$esg 15) <ow $an! $ini$%$ dri0es are reE%ired to create 76 8 7A&+ 6) ? Answer / Do% need to ha0e at #east - disk dri0es to create 76. 16) 'an !o% na$e so$e of the states of 7A&+ arra! ? Answer / There are states of 7A&+ arra!s that re"resent the stat%s of the 7A&+ arra!s which are gi0en be#ow on#ine +egraded 7eb%i#ding Fai#ed 11) Na$e the feat%res of S'S&-- standard ? Answer / FAS/ F%ick arbitration and se#ection +o$ain 2a#idation '7'/ '!c#ic red%ndanc! check 1>) 'an we assign a hot s"are to 7: 87A&+ :)arra!? Answer /No, since 7: is not red%ndant arra!, fai#%re of an! disks res%#ts in fai#%re of the entire arra! so we cannot reb%i#d the hot s"are for the 7: arra!. 1?) 'an !o% na$e so$e of the a0ai#ab#e ta"e $edia t!"es ?
Answer /There are $an! t!"es of ta"e $edia a0ai#ab#e to back %" the data so$e of the$ are +9T /digita# #inear ta"e - techno#og! for ta"e back%"/archi0e of networks and ser0ersG +9T techno#og! addresses $idrange to high-end ta"e back%" reE%ire$ents. 9T* /#inear ta"e o"enG a new standard ta"e for$at de0e#o"ed b! <4, &)3, and Seagate. A&T /ad0anced inte##igent ta"eG a he#ica# scan techno#og! de0e#o"ed b! Son! for ta"e back%"/archi0e of networks and ser0ers, s"ecifica##! addressing $idrange to high-end back%" reE%ire$ents. 1A) what is <A ? Answer / <A <igh A0ai#abi#it! is a techno#og! to achi0e fai#o0er with 0er! #ess #atenc!. &ts a "ractica# reE%ire$ent of data centers these da!s when c%sto$ers e."ect the ser0ers to be r%nning 5 ho%rs on a## > da!s aro%nd the who#e -16 da!s a !ear - %s%a##! referred as 5.>.-16. So to achie0e this a red%ndant infrastr%ct%re is created to $ake s%re if one database ser0er or if one a"" ser0er fai#s there is a re"#ica +atabase or A""ser0er read! to takeo0er the o"erations. End c%sto$er ne0er e."eriences an! o%tage when there is a <A network infrastr%ct%re. :) What is 0irt%a#iHation? Answer /2irt%a#iHation is #ogica# re"resentation of "h!sica# de0ices. &t is the techniE%e of $anaging and "resenting storage de0ices and reso%rces f%nctiona##!, regard#ess of their "h!sica# #a!o%t or #ocation.2irt%a#iHation is the "oo#ing of "h!sica# storage fro$ $%#ti"#e network storage de0ices into what a""ears to be a sing#e storage de0ice that is $anaged fro$ a centra# conso#e. Storage 0irt%a#iHation is co$$on#! %sed in a storage area network 8SAN). The $anage$ent of storage de0ices can be tedio%s and ti$e-cons%$ing. Storage 0irt%a#iHation he#"s the storage ad$inistrator "erfor$ the tasks of back%", archi0ing, and reco0er! $ore easi#!, and in #ess ti$e, b! disg%ising the act%a# co$"#e.it! of the SAN. 1. What are the ad0antages of SAN ? 3assi0e#! e.tended sca#abi#it! ;reat#! enhanced de0ice connecti0it! Storage conso#idation 9AN-free back%" Ser0er#ess 8acti0e-fabric) back%" Ser0er c#%stering <eterogeneo%s data sharing +isaster reco0er! - 7e$ote $irroring Whi#e answering "eo"#e do N*T "ortra! c#ear#! what the! $ean I what ad0antages each of the$ ha0e, which are cost effecti0e I which are to be %sed for the c#ient,s reE%ire$ents. . Whats the need for se"arate network for storage wh! 9AN can not be %sed? 9AN hardware and o"erating s!ste$s are geared to %ser traffic, and 9ANs are t%ned for a fast %ser res"onse to $essaging reE%ests.
With a SAN, the storage %nits can be sec%red se"arate#! fro$ the ser0ers and tota##! a"art fro$ the %ser network enhancing storage access in data b#ocks8b%#k data transfers), ad0antage%os for ser0er#ess back%"s. -. What are the ad0antages of 7A&+ ? J7ed%ndant Arra! of &ne."ensi0e +isksK +e"ending on how we config%re the arra!, we can ha0e the - data $irrored L7A&+ :M 8d%"#icate co"ies on se"arate dri0es) - stri"ed L7A&+ 1M 8inter#ea0ed across se0era# dri0es), or - "arit! "rotected L7A&+ 6M8e.tra data written to identif! errors). These can be %sed in co$bination to de#ier the ba#ance of "erfor$ance and re#iabi#it! that the %ser reE%ires. 5. When ()*+,s are %sed ? J(%st a )%nch of +isksK &t is a co##ection of disks that share a co$$on connection to the ser0er, b%t donBt inc#%de the $irroring, stri"ing, or "arit! faci#ities that 7A&+ s!ste$s do, b%t these ca"abi#ities are a0ai#ab#e with host-based software. 6. +ifferentiate 7A&+ I ()*+ ? 7A&+/ J7ed%ndant Arra! of &ne."ensi0e +isksK Fa%#t-to#erant gro%"ing of disks that ser0er sees as a sing#e disk 0o#%$e 'o$bination of "arit!-checking, $irroring, stri"ing Se#f-contained, $anageab#e %nit of storage ()*+/ J(%st a )%nch of +isksK +ri0es inde"endent#! attached to the &/* channe# Sca#eab#e, b%t reE%ires ser0er to $anage $%#ti"#e 0o#%$es +o not "ro0ide "rotection in case of dri0e fai#%re 1. What is a <)A ? <ost b%s ada"ters 8<)As) are needed to connect the ser0er8host) to the storage. 1) What is the difference between 7A&+ :, 7A&+ 1 and 7A&+ 6? 7A&+ : NO 4#ain stri"ing t!"ica##! with 5kb, 65kb or 1 ?kb stri"e siHe 7A&+ 1 NO 3irroring 7A&+ 6 NO Stri""ing with "arit! >) +escribe in brief the co$"osition of F' Fra$e? Start of the Fra$e #ocator Fra$e header 8inc#%des destination id and so%rce id, 5 b!tes/1 words) +ata 4a!#oad 8enca"s%#ate S'S& instr%ction can be :- 11 b!tes in #ength) '7' 8error checking, 5 b!tes) End of Fra$e 81 b!te) ?) What is storage 0irt%a#iHation? Storage 0irt%a#iHation is a$a#ga$ation of $%#ti"#e n/w storage de0ices into sing#e storage %nit.
A) What are the "rotoco#s %sed in "h!sica#/data#ink and network #a!er of SAN? a) Ethernet b) S'S& c) Fibre 'hanne# -:) What are the t!"es of disk arra! %sed in SAN? a) ()*+ b) 7A&+ -1) What are different t!"es of "rotoco#s %sed in trans"ortation and session #a!ers of SAN? a) Fibre 'hanne# 4rotoco# 8F'4) b) &nternet S'S& 8iS'S&) c) Fibre 'hanne# &4 8F'&4) - ) What is the t!"e of Encoding %sed in Fibre 'hanne#? ?b/1:b, as the encoding techniE%e is ab#e to detect a## $ost a## the bit errors --) <ow $an! c#asses of ser0ice are a0ai#ab#e in Fibre 'hanne#? > '#asses of ser0ice -5) What are the $ain constrains of S'S& in storage networking? a) +e"#o!$ent distance 8$a.. of 6 $ts) b) N%$ber of de0ices that can be interconnected 811) -6) What is a Fabric? &nterconnection of Fibre 'hanne# Switches -1) What are the ser0ices "ro0ided b! Fabric to a## the nodes? a) Fabric 9ogin b) SNS c) Fabric Address Notification d) 7egistered state change notification e) )roadcast Ser0ers ->) What is the difference between 9=N and WWN? 9=N/ %niE%e n%$ber that is assigned to each storage de0ice or "artition of the storage that the storage can s%""ort. WWN/ 15bit address that is hard coded into a fibre channe# <)A and this is %sed to identif! indi0id%a# "ort 8NP4ort or FP4ort) in the fabric. -?) What are the different to"o#ogies in Fibre 'hanne#? a) 4oint-to-4oint b) Arbitrar! 9oo" c) Switched Fabric 9oo" -A) What are the #a!ers of Fibre 'hanne# 4rotoco#? a) F' 4h!sica# 3edia b) F' Encoder and +ecoder c) F' Fra$ing and F#ow contro# d) F' 'o$$on Ser0ices e) F' =""er 9e0e# 4rotoco# 3a""ing
5:) What is Honing? Fabric $anage$ent ser0ice that can be %sed to create #ogica# s%bsets of de0ices within a SAN. This enab#es "ortioning of reso%rces for $anage$ent and access contro# "%r"ose. 51) What are the two $aQor c#assification of Honing? Two t!"es of Honing are a) Software Roning b) <ardware Roning 5 ) What are different #e0e#s of Honing? a) 4ort 9e0e# Honing b) WWN 9e0e# Honing c) +e0ice 9e0e# Honing d) 4rotoco# 9e0e# Honing e) 9=N 9e0e# Honing 5-) What are the - "ro$inent characteristics of SAS 4rotoco#? a) Nati0e 'o$$and F%e%ing 8N'F) b) 4ort 3%#ti"#ier c) 4ort Se#ector 55) What are the 6 states of Arbitrar! 9oo" in F'? a) 9oo" &nitia#iHation b) 9oo" 3onitoring c) 9oo" arbitration d) *"en 9oo" e) '#ose 9oo" 56) <ow does F' Switch $aintain the addresses? F' Switch %ses si$"#e na$e ser0er to $aintain the $a""ing tab#e 51) What is the "%r"ose of disk arra!? 4robabi#it! of %na0ai#abi#it! of data stored on the disk arra! d%e to sing#e "oint fai#%re is tota##! e#i$inated. 5>) What is disk arra!? Set of high "erfor$ance storage disks that can store se0era# terab!tes of data. Sing#e disk arra! can s%""ort $%#ti"#e "oints of connection to the network. 5?) What is 0irt%a#iHation? A techniE%e of hiding the "h!sica# characteristics of co$"%ter reso%rces fro$ the wa! in which other s!ste$ a""#ication or end %ser interact with those reso%rces. Aggregation, s"anning or concatenation of the co$bined $%#ti"#e reso%rces into #arger reso%rce "oo#s. 5A) What is 3%#ti"ath &/*? Fa%#t to#erant techniE%e where b! there is $ore than one "h!sica# "ath between the '4= in the co$"%ter s!ste$s and its $ain storage de0ices thro%gh the b%ses, contro##ers, switches and other bridge de0ices connecting the$. 6:) What is 7A&+?
Techno#og! that gro%"s se0era# "h!sica# dri0es in a co$"%ter into an arra! that !o% can define as one or $ore #ogica# dri0e. Each #ogica# dri0e a""ears to the o"erating s!ste$ as sing#e dri0e. This gro%"ing enhances the "erfor$ance of the #ogica# dri0e be!ond the "h!sica# ca"abi#it! of the dri0es. 61) What is stri"e-%nit-siHe? &t is data distrib%tion sche$e that co$"#e$ent s the wa! o"erating s!ste$ reE%est data. ;ran%#arit! at which data is stored on one dri0e of the arra! before s%bseE%ent data is stored on the ne.t dri0e of the arra!. Stri"e %nit siHe sho%#d be c#ose to the siHe of the s!ste$ &/* reE%est. 6 ) What is 9=N 3asking? A $ethod %sed to create an e.c#%si0e storage area and access contro#. And this can be achie0ed b!e storage de0ice contro# "rogra$. 6-) What is the s$a##est %nit of infor$ation transfer in F'? Fra$e 65) <ow is the ca"acit! of the <++ ca#c%#ated? N%$ber of <eads C N%$ber of '!#inders C Sectors "er track C Sector SiHe 66) What is bad b#ock rea##ocation? A bad sector is re$a""ed or rea##ocated to good s"are b#ock and this infor$ation is stored in the interna# tab#e on the hard disk dri0e. The bad b#ocks are identified d%ring the $edia test of the <++ as we## as d%ring 0ario%s t!"es of read write o"erations "erfor$ed d%ring the &/* tests. A"art fro$ the new generation of <++ co$es with a techno#og! ca##ed );3S 8backgro%nd $edia scan) which contin%o%s#! scans the <++ $edia for defects and $a"s the$ when the dri0e is id#e 8this is "erfor$ed after the <++ is attached to the s!ste$). 61) What are tow t!"es of recording techniE%es on the ta"es? a) 9inear 7ecording b) <e#ica# Scan 7ecording. 6>) What is sna" shot? A sna"shot of data obQect contains an i$age of data at a "artic%#ar "oint of ti$e. 6?) What is <S3? <ierarchica# storage $anage$ent, an a""#ication that atte$"ts to $atch the "riorit! of data with the cost of storage. 6A) What is hot-swa""ing? +e0ices are a##owed to be re$o0ed and inserted into a s!ste$ witho%t t%rning off the s!ste$. 1:) What is <ot-S"aring? A s"are de0ice is a0ai#ab#e to be inserted into the s%bs!ste$ o"eration witho%t ha0ing to re$o0e and re"#ace a de0ice. 11) What are different t!"es of back%" s!ste$? a) *ff#ine b) *n#ine
c) Near 9ine 1 ) What is the different between $irroring, 7o%ting and $%#ti"athing? 7ed%ndanc! F%nctions 7e#ationshi"s 7o#e 3irroring ;enerates i/os to storage targets 'reates co"ies of data 7o%ting +eter$ined b! switches inde"endent of S'S& 7ecreates n/w ro%te after a fai#%re 3%#ti"athing Two initiator to one target Se#ects the 9=N initiator "air to %se 1-) Na$e few t!"es of Ta"e storage? a) +igita# 9inear Ta"e b) Ad0anced &nte##igent Ta"e c) 9inear Ta"e *"en 15) What is a seE%ence in F'? ;ro%" of one or $ore fra$es that enco$"asses one or $ore Jinfor$ation %nitsK of a %""er #a!er "rotoco#. E.a$"#e/ &t reE%ires i) *ne seE%ence to transfer the co$$and ii) *ne or $ore seE%ence to transfer the data iii) *nce seE%ence to transfer the stat%s. 16) What is E.change in F'? E.change is to estab#ish a re#ationshi" between NP4*7Ts and then these two "orts transfer data 0ia one or $ore seE%ence within this re#ationshi". E.a$"#e/ E.change e.ist to transfer the co$$and, data and the stat%s of one S'S& task 11) What is E.change in F'8Fibre 'hanne#)? E.change is to estab#ish a re#ationshi" between NP4*7Ts and then these two "orts transfer data 0ia one or $ore seE%ence within this re#ationshi". E.a$"#e/ E.change e.ist to transfer the co$$and, data and the stat%s of one S'S& task 1>) Wh! do we need 9ogin in F'? 4ort 9ogin/ To e.change ser0ice "ara$eters between NP4orts and NP4orts 4rocess 9ogin/ To estab#ish the S'S& o"erating en0iron$ent between two NP4*7TS 1?) What are the different t!"es of c#%sters? a) <igh a0ai#abi#it! c#%sters b) <igh 4erfor$ance '#%sters c) 9oad )a#ancing '#%sters. 1A) What are three #e0e#s of $anage$ent in storage? a) Storage 9e0e# 3anage$ent b) Network 9e0e# 3anage$ent c) Enter"rise 9e0e# 3anage$ent. >:) What are the ke! acti0ities in SAN $anage$ent? a) 3onitoring
b) 'onfig%ring c) 'ontro##ing d) Tro%b#eshooting e) +iagnosing >1) What is the difference between <)A and N&'? <)A NO <ost b%s ada"ters are %sed in storage based traffic whi#e N&' 8Network &nterface 'ards are %sed in &4 based 9AN traffic. > ) What is the $eas%ring %nit of data acti0it!? ;igabits "er ho%r >-) What are the basic storage "o#icies? a) Sec%rit! and a%thentication b) 'a"acit!, 'ontent and E%ota $anage$ent c) F%a#it! of Ser0ice >5) What is b!"ass circ%itr!? A circ%it that a%to$atica##! re$o0es the storage de0ice fro$ the data "ath 8F' de0ice o%t of F' A9 #oo") when signa#ing is #ost 8this signa# is ca##ed "ort b!-"ass signa#). >6) E."#ain different c#asses of ser0ice in F'? '#ass 1/ dedicated connection between two co$$%nicators with acknow#edge$ent of fra$e de#i0er!. '#ass / is connection #ess b%t "ro0ides acknow#edge$ent '#ass -/ is connection #ess and "ro0ides no notification of de#i0er! '#ass 5/ a##ows fractiona# bandwidth for 0irt%a# circ%its '#ass 6/ 4ro0ides $%#ticast with acknow#edg$ent '#ass F/ &s %sed for switch to switch co$$%nication in the fabric. >1) <ow $an! connections are "ossib#e in Fabric to"o#og!? S 5 8 5 bit address to the "ort) , and the #argest "ossib#e fabric wi## ha0e -A interconnected switches. >>) What is one of the constrains of %sing storage switch? 9atenc! >?) What is the difference between NAS and SAN? NAS 'ab#es %sed in the n/w n/w "rotoco#s 8T'4/&4, &4.) and fi#e sharing "rotoco#s 8&FS I NFS) 9ower T'* S%""ort heterogeneo%s c#ients S#ow SAN <igh-s"eed connecti0it! s%ch as F' +o not %se n/w "rotoco#s beca%se data reE%est are not $ade o0er 9AN <igher T'* 7eE%ires s"ecia# s/w to "ro0ide access to heterogeneo%s c#ients
Fast >A) What is (itter? (itter refers to an! de0iation in ti$ing that a bit strea$ s%ffers as it tra0erses the "h!sica# $edi%$ and the circ%itr! on-board the end de0ices. A certain a$o%nt of de0iation fro$ the origina# signa#ing wi## occ%r nat%ra##! as seria# bit strea$ "ro"agates o0er fibre-o"tic or co""er cab#ing. 3ain#! ca%sed b! e#ectro $agnetic interference ?:) What is )E7/)it error rate? 4robabi#it! that a trans$itted bit wi## be erroneo%s#! recei0ed is the $eas%re of n%$ber of bits 8erroneo%s) at the o%t"%t of the recei0er and di0iding b! the tota# n%$ber of bits in trans$ission. ?1) What is WW4N? WW4N is the 11bit character that is assigned to the "ort, SAN 0o#%$e contro##er %ses it to %niE%e#! identif! the fibre channe# <)A that is insta##ed in the host s!ste$. ? ) What is connection a##egiance? ;i0en $%#ti"#e connections are estab#ished, indi0id%a# co$$and/res"onse "air $%st f#ow o0er the sa$e connection. This connection a##egiance ens%res that s"ecific read or writes co$$ands are f%#fi##ed witho%t the additiona# o0erhead of $onitoring $%#ti"#e connections and to see whether a "artic%#ar reE%est is co$"#eted. ?-) What is b%rst 9ength? The b%rst #ength is the n%$ber of b!tes that the S'S& initiator sends to the S'S& target in the F'4P+ATA seE%ence. ?5) E."#ain different t!"es of 7A&+? 7A&+ :/ data stri"ing b#ocks are written seE%entia##!, no red%ndanc!, high "erfor$ance than sing#e disk access. 7A&+ 1/ 3irroring, data b#ocks written to both disk at once, 1::T red%ndanc!, 1::T additiona# ca"acit! reE%ired. 7ead can be distrib%ted across both the disks to increase "erfor$ance. 7A&+ -/ Stri"ing with b!te "arit!, adds "arit! infor$ation to reb%i#d data in the e0ent of disk fai#%re, high transfer rate and a0ai#abi#it! with #ower ca"acit! reE%ired than 7A&+ 1. Transactions "erfor$ance #ow beca%se a## disks o"erate in #ock ste". 7A&+ 5/ stri"ing with b#ock "arit!, inde"endent#! accessib#e disks, data b#ocks written seE%entia##! to each disk fai#%re. +edicated "arit! disk is write bott#eneck and #eads to "oor "erfor$ance. 7A&+ 6/ Stri"ing with rotationa# "arit!, "arit! b#ocks written "er row and distrib%ted across a## disks, "arit! distrib%tion e#i$inates sing#e write bott#eneck o0erhead for "arit! ca#c%#ation on write s%""#e$ented with "ara##e# $icro"rocessors or caching. 85) What is NAS in detail ? NAS or Network Attached Storage JNAS is %sed to refer to storage e#e$ents that connect to a network and "ro0ide fi#e access ser0ices to co$"%ter s!ste$s. Abbre0iated NAS. A NAS Storage E#e$ent
consists of an interface or engine, which i$"#e$ents the fi#e ser0ices, and one or $ore de0ices, on which data is stored. NAS e#e$ents $a! be attached to an! t!"e of network. When attached to SANs, NAS e#e$ents $a! be considered to be $e$bers of the SAS 8SAN Attached Storage) c#ass of storage e#e$ents. A c#ass of s!ste$s that "ro0ide fi#e ser0ices to host co$"%ters. A host s!ste$ that %ses network attached storage %ses a fi#e s!ste$ de0ice dri0er to access data %sing fi#e access "rotoco#s s%ch as NFS or '&FS. NAS s!ste$s inter"ret these co$$ands and "erfor$ the interna# fi#e and de0ice &/* o"erations necessar! to e.ec%te the$.K Tho%gh the NAS does s"eed %" b%#k transfers, it does not off#oad the 9AN #ike a SAN does. 3ost storage de0ices cannot Q%st "#%g into gigabit Ethernet and be shared this reE%ires a s"ecia#iHed fi#e ser0er the 0ariet! of s%""orted de0ices is $ore #i$ited.NAS has 0ario%s "rotoco#s estab#ished for s%ch needed feat%res as disco0er!, access contro#, and na$e ser0ices. 86)Briefly list the advantages of SAN ? SANs f%##! e."#oit high-"erfor$ance, highconnecti0it! network techno#ogies SANs e."and easi#! to kee" "ace with fast growing storage needs SANs a##ow an! ser0er to access an! data SANs he#" centra#iHe $anage$ent of storage reso%rces SANs red%ce tota# cost of ownershi" 8T'*) So$e $ore FAFs 1)What is the $ost critica# co$"onent in SAN? )What is the defa%#t id for S'S& <)A? -)What is "ara##e#is$? 5)What do !o% know abo%t SAN testing? 6)E."#ain a t!"ica# SAN #andsca"e? 1)What is fan-in and fan-o%t in SAN 2irt%a#iHation s!ste$? >)<ow is the intero"erabi#it! between the ser0er and the storage is achie0ed? ?)What are the "erfor$ance $etrics of SAN? A)What do !o% know abo%t &/* $eters , their t!"es and how are the %sed? 1:)What is the eE%i0a#ent of Address reso#%tion "rotoco# in storage? 11)What is $eant b! a0ai#abi#it! I re#iabi#it! in Storage ? 1 )What is +isaster 7eco0er! I how it is i$"#e$ented in a Storage en0iron$ent? 1-)E.a$"#e for fai#o0er c#%ster config%rations ? 15)What are the needs/ad0antages of Storage conso#idation ?
>) Which one is the +efa%#t &+ for S'S& <)A ? ;enera##! the defa%#t &+ for S'S& <)A is >. S'S&- S$a## 'o$"%ter S!ste$ &nterface
<)A - <ost )%s Ada"tor ?) <ow do !o% insta## de0ice dri0ers for the <)A first ti$e d%ring *S insta##ation ? &n so$e scenarios !o% are s%""osed to insta## *"erating S!ste$ on the dri0es connected thr% S'S& <)A or S'S& 7A&+ 'onro##ers,b%t $ost of the *S,es wi## not be %"dated with dri0ers for those contro##ers,that ti$e !o% need to s%""#! dri0ers e.terna##!,if !o% are insta##ing windows ,!o% need to "ress F1 d%ring the insta##ion of *S and "ro0ide the dri0er disk or '+ which ca$e a#ong with <)A. &f !o% are insta##ing #in%. !o% need to t!"e @#in%. dd@ for insta##ing an! dri0er. A) What is Arra! ? Arra! is a gro%" of &nde"endent "h!sica# disks to config%re an! 2o#%$es or 7A&+ 0o#%$es. 1:)'an % describe at#east - tro%b#eshooting scenarios which !o% ha0e co$e across in detai# ? S'ENA7&* 1/<ow do !o% find/deb%g when there is error whi#e working S'S& de0ices? &n o%r dai#! SAN tro%b#eshooting there are $an! $anage$ent and config%ration too#s we %se the$ to see when there is a fai#%re with target de0ice or initiator de0ice. So$e ti$e it is e0en hard to tro%b#e shoot so$e of the things s%ch as $edia errors in the dri0es, or so$e of the dri0es taking #ong ti$e to s"inn%".&n s%ch cases these %ti#ities wi## not co$e to he#".To deb%g this kind of infor$ation $ost of the contro##er wi## be i$"#e$ented with --"in seria# deb%g "ort. With seria# "ort deb%g connector cab#e !o% can co##ect the deb%g infor$ation with h!"er ter$ina# software. S'ENA7&* / & a$ ha0ing an iss%e with a contro##er its taking #ot of ti$e to boot and detect a## the dri0es connected how can & so#0e this.? There are $an! "ossibi#ities that $ight ca%se this "rob#e$. *ne of the reason $ight be !o% are %sing bad dri0es that cannot be re"aired . &n those cases !o% re"#ace the disks with working ones. Another reason $ight be s#ots !o% connected !o%r contro##er to a s#ot which $ight not be s%""orted. Tr! to connect with other t!"es of s#ots. *ne $ore "robab#e reason is if !o% ha0e f#ashed the fir$ware for different *E3Bs on the sa$e hardware. To get rid of this the f#ash %ti#ities wi## be ha0ing o"tion to erase a## the "re0io%s and EE47*3 and boot b#ock entr! o"tion. =se that o"tion to rectif! the "rob#e$. S'ENA7&* -/ & a$ %sing ta"e dri0e series >::C , e0en the 0endor infor$ation
on the Ta"e dri0e sa!s >::C, b%t the 4*ST infor$ation whi#e booting the ser0er is showing as 6::C what co%#d be the "rob#e$? First !o% sho%#d $ake s%re !o%r hardware is of which series , !o% can find o%t this in the "rod%ct website. ;enera##! !o% can see this beca%se in $ost of the testing co$"anies the! %se sa$e hardware to test different series of sa$e hardware t!"e. What the! do is the! f#ash the different series fir$ware. Do% can a#wa!s f#ash back to e.act hardware t!"e. 11.Which are the SAN to"o#ogies? Answer /SAN can be connected in - t!"es which are $entioned be#ow/ 4oint to 4oint to"o#og! F' Arbitrated 9oo" 8 F' /Fibre 'hanne# ) Switched Fabric 1 ) Which are the 5 t!"es of SAN architect%re t!"es Answer /'ore-edge F%##-3esh 4artia#-3esh 'ascade 1-) which co$$and is %sed in #in%. to know the dri0er 0ersion of an! hardware de0ice ? Answer / d$esg 15) <ow $an! $ini$%$ dri0es are reE%ired to create 76 8 7A&+ 6) ? Answer / Do% need to ha0e at #east - disk dri0es to create 76. 16) 'an !o% na$e so$e of the states of 7A&+ arra! ? Answer / There are states of 7A&+ arra!s that re"resent the stat%s of the 7A&+ arra!s which are gi0en be#ow on#ine +egraded 7eb%i#ding Fai#ed 11) Na$e the feat%res of S'S&-- standard ? Answer / FAS/ F%ick arbitration and se#ection +o$ain 2a#idation '7'/ '!c#ic red%ndanc! check 1>) 'an we assign a hot s"are to 7: 87A&+ :)arra!? Answer /No, since 7: is not red%ndant arra!, fai#%re of an! disks res%#ts in fai#%re of the entire arra! so we cannot reb%i#d the hot s"are for the 7: arra!. 1?) 'an !o% na$e so$e of the a0ai#ab#e ta"e $edia t!"es ?
Answer /There are $an! t!"es of ta"e $edia a0ai#ab#e to back %" the data so$e of the$ are +9T /digita# #inear ta"e - techno#og! for ta"e back%"/archi0e of networks and ser0ersG +9T techno#og! addresses $idrange to high-end ta"e back%" reE%ire$ents. 9T* /#inear ta"e o"enG a new standard ta"e for$at de0e#o"ed b! <4, &)3, and Seagate. A&T /ad0anced inte##igent ta"eG a he#ica# scan techno#og! de0e#o"ed b! Son! for ta"e back%"/archi0e of networks and ser0ers, s"ecifica##! addressing $idrange to high-end back%" reE%ire$ents. 1A) what is <A ? Answer / <A <igh A0ai#abi#it! is a techno#og! to achi0e fai#o0er with 0er! #ess #atenc!. &ts a "ractica# reE%ire$ent of data centers these da!s when c%sto$ers e."ect the ser0ers to be r%nning 5 ho%rs on a## > da!s aro%nd the who#e -16 da!s a !ear - %s%a##! referred as 5.>.-16. So to achie0e this a red%ndant infrastr%ct%re is created to $ake s%re if one database ser0er or if one a"" ser0er fai#s there is a re"#ica +atabase or A""ser0er read! to takeo0er the o"erations. End c%sto$er ne0er e."eriences an! o%tage when there is a <A network infrastr%ct%re. :) What is 0irt%a#iHation? Answer /2irt%a#iHation is #ogica# re"resentation of "h!sica# de0ices. &t is the techniE%e of $anaging and "resenting storage de0ices and reso%rces f%nctiona##!, regard#ess of their "h!sica# #a!o%t or #ocation.2irt%a#iHation is the "oo#ing of "h!sica# storage fro$ $%#ti"#e network storage de0ices into what a""ears to be a sing#e storage de0ice that is $anaged fro$ a centra# conso#e. Storage 0irt%a#iHation is co$$on#! %sed in a storage area network 8SAN). The $anage$ent of storage de0ices can be tedio%s and ti$e-cons%$ing. Storage 0irt%a#iHation he#"s the storage ad$inistrator "erfor$ the tasks of back%", archi0ing, and reco0er! $ore easi#!, and in #ess ti$e, b! disg%ising the act%a# co$"#e.it! of the SAN. 1. What are the ad0antages of SAN ? 3assi0e#! e.tended sca#abi#it! ;reat#! enhanced de0ice connecti0it! Storage conso#idation 9AN-free back%" Ser0er#ess 8acti0e-fabric) back%" Ser0er c#%stering <eterogeneo%s data sharing +isaster reco0er! - 7e$ote $irroring Whi#e answering "eo"#e do N*T "ortra! c#ear#! what the! $ean I what ad0antages each of the$ ha0e, which are cost effecti0e I which are to be %sed for the c#ient,s reE%ire$ents. . Whats the need for se"arate network for storage wh! 9AN can not be %sed? 9AN hardware and o"erating s!ste$s are geared to %ser traffic, and 9ANs are t%ned for a fast %ser res"onse to $essaging reE%ests.
With a SAN, the storage %nits can be sec%red se"arate#! fro$ the ser0ers and tota##! a"art fro$ the %ser network enhancing storage access in data b#ocks8b%#k data transfers), ad0antage%os for ser0er#ess back%"s. -. What are the ad0antages of 7A&+ ? J7ed%ndant Arra! of &ne."ensi0e +isksK +e"ending on how we config%re the arra!, we can ha0e the - data $irrored L7A&+ :M 8d%"#icate co"ies on se"arate dri0es) - stri"ed L7A&+ 1M 8inter#ea0ed across se0era# dri0es), or - "arit! "rotected L7A&+ 6M8e.tra data written to identif! errors). These can be %sed in co$bination to de#ier the ba#ance of "erfor$ance and re#iabi#it! that the %ser reE%ires. 5. When ()*+,s are %sed ? J(%st a )%nch of +isksK &t is a co##ection of disks that share a co$$on connection to the ser0er, b%t donBt inc#%de the $irroring, stri"ing, or "arit! faci#ities that 7A&+ s!ste$s do, b%t these ca"abi#ities are a0ai#ab#e with host-based software. 6. +ifferentiate 7A&+ I ()*+ ? 7A&+/ J7ed%ndant Arra! of &ne."ensi0e +isksK Fa%#t-to#erant gro%"ing of disks that ser0er sees as a sing#e disk 0o#%$e 'o$bination of "arit!-checking, $irroring, stri"ing Se#f-contained, $anageab#e %nit of storage ()*+/ J(%st a )%nch of +isksK +ri0es inde"endent#! attached to the &/* channe# Sca#eab#e, b%t reE%ires ser0er to $anage $%#ti"#e 0o#%$es +o not "ro0ide "rotection in case of dri0e fai#%re 1. What is a <)A ? <ost b%s ada"ters 8<)As) are needed to connect the ser0er8host) to the storage. 1) What is the difference between 7A&+ :, 7A&+ 1 and 7A&+ 6? 7A&+ : NO 4#ain stri"ing t!"ica##! with 5kb, 65kb or 1 ?kb stri"e siHe 7A&+ 1 NO 3irroring 7A&+ 6 NO Stri""ing with "arit! >) +escribe in brief the co$"osition of F' Fra$e? Start of the Fra$e #ocator Fra$e header 8inc#%des destination id and so%rce id, 5 b!tes/1 words) +ata 4a!#oad 8enca"s%#ate S'S& instr%ction can be :- 11 b!tes in #ength) '7' 8error checking, 5 b!tes) End of Fra$e 81 b!te) ?) What is storage 0irt%a#iHation? Storage 0irt%a#iHation is a$a#ga$ation of $%#ti"#e n/w storage de0ices into sing#e storage %nit.
A) What are the "rotoco#s %sed in "h!sica#/data#ink and network #a!er of SAN? a) Ethernet b) S'S& c) Fibre 'hanne# -:) What are the t!"es of disk arra! %sed in SAN? a) ()*+ b) 7A&+ -1) What are different t!"es of "rotoco#s %sed in trans"ortation and session #a!ers of SAN? a) Fibre 'hanne# 4rotoco# 8F'4) b) &nternet S'S& 8iS'S&) c) Fibre 'hanne# &4 8F'&4) - ) What is the t!"e of Encoding %sed in Fibre 'hanne#? ?b/1:b, as the encoding techniE%e is ab#e to detect a## $ost a## the bit errors --) <ow $an! c#asses of ser0ice are a0ai#ab#e in Fibre 'hanne#? > '#asses of ser0ice -5) What are the $ain constrains of S'S& in storage networking? a) +e"#o!$ent distance 8$a.. of 6 $ts) b) N%$ber of de0ices that can be interconnected 811) -6) What is a Fabric? &nterconnection of Fibre 'hanne# Switches -1) What are the ser0ices "ro0ided b! Fabric to a## the nodes? a) Fabric 9ogin b) SNS c) Fabric Address Notification d) 7egistered state change notification e) )roadcast Ser0ers ->) What is the difference between 9=N and WWN? 9=N/ %niE%e n%$ber that is assigned to each storage de0ice or "artition of the storage that the storage can s%""ort. WWN/ 15bit address that is hard coded into a fibre channe# <)A and this is %sed to identif! indi0id%a# "ort 8NP4ort or FP4ort) in the fabric. -?) What are the different to"o#ogies in Fibre 'hanne#? a) 4oint-to-4oint b) Arbitrar! 9oo" c) Switched Fabric 9oo" -A) What are the #a!ers of Fibre 'hanne# 4rotoco#? a) F' 4h!sica# 3edia b) F' Encoder and +ecoder c) F' Fra$ing and F#ow contro# d) F' 'o$$on Ser0ices e) F' =""er 9e0e# 4rotoco# 3a""ing
5:) What is Honing? Fabric $anage$ent ser0ice that can be %sed to create #ogica# s%bsets of de0ices within a SAN. This enab#es "ortioning of reso%rces for $anage$ent and access contro# "%r"ose. 51) What are the two $aQor c#assification of Honing? Two t!"es of Honing are a) Software Roning b) <ardware Roning 5 ) What are different #e0e#s of Honing? a) 4ort 9e0e# Honing b) WWN 9e0e# Honing c) +e0ice 9e0e# Honing d) 4rotoco# 9e0e# Honing e) 9=N 9e0e# Honing 5-) What are the - "ro$inent characteristics of SAS 4rotoco#? a) Nati0e 'o$$and F%e%ing 8N'F) b) 4ort 3%#ti"#ier c) 4ort Se#ector 55) What are the 6 states of Arbitrar! 9oo" in F'? a) 9oo" &nitia#iHation b) 9oo" 3onitoring c) 9oo" arbitration d) *"en 9oo" e) '#ose 9oo" 56) <ow does F' Switch $aintain the addresses? F' Switch %ses si$"#e na$e ser0er to $aintain the $a""ing tab#e 51) What is the "%r"ose of disk arra!? 4robabi#it! of %na0ai#abi#it! of data stored on the disk arra! d%e to sing#e "oint fai#%re is tota##! e#i$inated. 5>) What is disk arra!? Set of high "erfor$ance storage disks that can store se0era# terab!tes of data. Sing#e disk arra! can s%""ort $%#ti"#e "oints of connection to the network. 5?) What is 0irt%a#iHation? A techniE%e of hiding the "h!sica# characteristics of co$"%ter reso%rces fro$ the wa! in which other s!ste$ a""#ication or end %ser interact with those reso%rces. Aggregation, s"anning or concatenation of the co$bined $%#ti"#e reso%rces into #arger reso%rce "oo#s. 5A) What is 3%#ti"ath &/*? Fa%#t to#erant techniE%e where b! there is $ore than one "h!sica# "ath between the '4= in the co$"%ter s!ste$s and its $ain storage de0ices thro%gh the b%ses, contro##ers, switches and other bridge de0ices connecting the$. 6:) What is 7A&+?
Techno#og! that gro%"s se0era# "h!sica# dri0es in a co$"%ter into an arra! that !o% can define as one or $ore #ogica# dri0e. Each #ogica# dri0e a""ears to the o"erating s!ste$ as sing#e dri0e. This gro%"ing enhances the "erfor$ance of the #ogica# dri0e be!ond the "h!sica# ca"abi#it! of the dri0es. 61) What is stri"e-%nit-siHe? &t is data distrib%tion sche$e that co$"#e$ent s the wa! o"erating s!ste$ reE%est data. ;ran%#arit! at which data is stored on one dri0e of the arra! before s%bseE%ent data is stored on the ne.t dri0e of the arra!. Stri"e %nit siHe sho%#d be c#ose to the siHe of the s!ste$ &/* reE%est. 6 ) What is 9=N 3asking? A $ethod %sed to create an e.c#%si0e storage area and access contro#. And this can be achie0ed b!e storage de0ice contro# "rogra$. 6-) What is the s$a##est %nit of infor$ation transfer in F'? Fra$e 65) <ow is the ca"acit! of the <++ ca#c%#ated? N%$ber of <eads C N%$ber of '!#inders C Sectors "er track C Sector SiHe 66) What is bad b#ock rea##ocation? A bad sector is re$a""ed or rea##ocated to good s"are b#ock and this infor$ation is stored in the interna# tab#e on the hard disk dri0e. The bad b#ocks are identified d%ring the $edia test of the <++ as we## as d%ring 0ario%s t!"es of read write o"erations "erfor$ed d%ring the &/* tests. A"art fro$ the new generation of <++ co$es with a techno#og! ca##ed );3S 8backgro%nd $edia scan) which contin%o%s#! scans the <++ $edia for defects and $a"s the$ when the dri0e is id#e 8this is "erfor$ed after the <++ is attached to the s!ste$). 61) What are tow t!"es of recording techniE%es on the ta"es? a) 9inear 7ecording b) <e#ica# Scan 7ecording. 6>) What is sna" shot? A sna"shot of data obQect contains an i$age of data at a "artic%#ar "oint of ti$e. 6?) What is <S3? <ierarchica# storage $anage$ent, an a""#ication that atte$"ts to $atch the "riorit! of data with the cost of storage. 6A) What is hot-swa""ing? +e0ices are a##owed to be re$o0ed and inserted into a s!ste$ witho%t t%rning off the s!ste$. 1:) What is <ot-S"aring? A s"are de0ice is a0ai#ab#e to be inserted into the s%bs!ste$ o"eration witho%t ha0ing to re$o0e and re"#ace a de0ice. 11) What are different t!"es of back%" s!ste$? a) *ff#ine b) *n#ine
c) Near 9ine 1 ) What is the different between $irroring, 7o%ting and $%#ti"athing? 7ed%ndanc! F%nctions 7e#ationshi"s 7o#e 3irroring ;enerates i/os to storage targets 'reates co"ies of data 7o%ting +eter$ined b! switches inde"endent of S'S& 7ecreates n/w ro%te after a fai#%re 3%#ti"athing Two initiator to one target Se#ects the 9=N initiator "air to %se 1-) Na$e few t!"es of Ta"e storage? a) +igita# 9inear Ta"e b) Ad0anced &nte##igent Ta"e c) 9inear Ta"e *"en 15) What is a seE%ence in F'? ;ro%" of one or $ore fra$es that enco$"asses one or $ore Jinfor$ation %nitsK of a %""er #a!er "rotoco#. E.a$"#e/ &t reE%ires i) *ne seE%ence to transfer the co$$and ii) *ne or $ore seE%ence to transfer the data iii) *nce seE%ence to transfer the stat%s. 16) What is E.change in F'? E.change is to estab#ish a re#ationshi" between NP4*7Ts and then these two "orts transfer data 0ia one or $ore seE%ence within this re#ationshi". E.a$"#e/ E.change e.ist to transfer the co$$and, data and the stat%s of one S'S& task 11) What is E.change in F'8Fibre 'hanne#)? E.change is to estab#ish a re#ationshi" between NP4*7Ts and then these two "orts transfer data 0ia one or $ore seE%ence within this re#ationshi". E.a$"#e/ E.change e.ist to transfer the co$$and, data and the stat%s of one S'S& task 1>) Wh! do we need 9ogin in F'? 4ort 9ogin/ To e.change ser0ice "ara$eters between NP4orts and NP4orts 4rocess 9ogin/ To estab#ish the S'S& o"erating en0iron$ent between two NP4*7TS 1?) What are the different t!"es of c#%sters? a) <igh a0ai#abi#it! c#%sters b) <igh 4erfor$ance '#%sters c) 9oad )a#ancing '#%sters. 1A) What are three #e0e#s of $anage$ent in storage? a) Storage 9e0e# 3anage$ent b) Network 9e0e# 3anage$ent c) Enter"rise 9e0e# 3anage$ent. >:) What are the ke! acti0ities in SAN $anage$ent? a) 3onitoring
b) 'onfig%ring c) 'ontro##ing d) Tro%b#eshooting e) +iagnosing >1) What is the difference between <)A and N&'? <)A NO <ost b%s ada"ters are %sed in storage based traffic whi#e N&' 8Network &nterface 'ards are %sed in &4 based 9AN traffic. > ) What is the $eas%ring %nit of data acti0it!? ;igabits "er ho%r >-) What are the basic storage "o#icies? a) Sec%rit! and a%thentication b) 'a"acit!, 'ontent and E%ota $anage$ent c) F%a#it! of Ser0ice >5) What is b!"ass circ%itr!? A circ%it that a%to$atica##! re$o0es the storage de0ice fro$ the data "ath 8F' de0ice o%t of F' A9 #oo") when signa#ing is #ost 8this signa# is ca##ed "ort b!-"ass signa#). >6) E."#ain different c#asses of ser0ice in F'? '#ass 1/ dedicated connection between two co$$%nicators with acknow#edge$ent of fra$e de#i0er!. '#ass / is connection #ess b%t "ro0ides acknow#edge$ent '#ass -/ is connection #ess and "ro0ides no notification of de#i0er! '#ass 5/ a##ows fractiona# bandwidth for 0irt%a# circ%its '#ass 6/ 4ro0ides $%#ticast with acknow#edg$ent '#ass F/ &s %sed for switch to switch co$$%nication in the fabric. >1) <ow $an! connections are "ossib#e in Fabric to"o#og!? S 5 8 5 bit address to the "ort) , and the #argest "ossib#e fabric wi## ha0e -A interconnected switches. >>) What is one of the constrains of %sing storage switch? 9atenc! >?) What is the difference between NAS and SAN? NAS 'ab#es %sed in the n/w n/w "rotoco#s 8T'4/&4, &4.) and fi#e sharing "rotoco#s 8&FS I NFS) 9ower T'* S%""ort heterogeneo%s c#ients S#ow SAN <igh-s"eed connecti0it! s%ch as F' +o not %se n/w "rotoco#s beca%se data reE%est are not $ade o0er 9AN <igher T'* 7eE%ires s"ecia# s/w to "ro0ide access to heterogeneo%s c#ients
Fast >A) What is (itter? (itter refers to an! de0iation in ti$ing that a bit strea$ s%ffers as it tra0erses the "h!sica# $edi%$ and the circ%itr! on-board the end de0ices. A certain a$o%nt of de0iation fro$ the origina# signa#ing wi## occ%r nat%ra##! as seria# bit strea$ "ro"agates o0er fibre-o"tic or co""er cab#ing. 3ain#! ca%sed b! e#ectro $agnetic interference ?:) What is )E7/)it error rate? 4robabi#it! that a trans$itted bit wi## be erroneo%s#! recei0ed is the $eas%re of n%$ber of bits 8erroneo%s) at the o%t"%t of the recei0er and di0iding b! the tota# n%$ber of bits in trans$ission. ?1) What is WW4N? WW4N is the 11bit character that is assigned to the "ort, SAN 0o#%$e contro##er %ses it to %niE%e#! identif! the fibre channe# <)A that is insta##ed in the host s!ste$. ? ) What is connection a##egiance? ;i0en $%#ti"#e connections are estab#ished, indi0id%a# co$$and/res"onse "air $%st f#ow o0er the sa$e connection. This connection a##egiance ens%res that s"ecific read or writes co$$ands are f%#fi##ed witho%t the additiona# o0erhead of $onitoring $%#ti"#e connections and to see whether a "artic%#ar reE%est is co$"#eted. ?-) What is b%rst 9ength? The b%rst #ength is the n%$ber of b!tes that the S'S& initiator sends to the S'S& target in the F'4P+ATA seE%ence. ?5) E."#ain different t!"es of 7A&+? 7A&+ :/ data stri"ing b#ocks are written seE%entia##!, no red%ndanc!, high "erfor$ance than sing#e disk access. 7A&+ 1/ 3irroring, data b#ocks written to both disk at once, 1::T red%ndanc!, 1::T additiona# ca"acit! reE%ired. 7ead can be distrib%ted across both the disks to increase "erfor$ance. 7A&+ -/ Stri"ing with b!te "arit!, adds "arit! infor$ation to reb%i#d data in the e0ent of disk fai#%re, high transfer rate and a0ai#abi#it! with #ower ca"acit! reE%ired than 7A&+ 1. Transactions "erfor$ance #ow beca%se a## disks o"erate in #ock ste". 7A&+ 5/ stri"ing with b#ock "arit!, inde"endent#! accessib#e disks, data b#ocks written seE%entia##! to each disk fai#%re. +edicated "arit! disk is write bott#eneck and #eads to "oor "erfor$ance. 7A&+ 6/ Stri"ing with rotationa# "arit!, "arit! b#ocks written "er row and distrib%ted across a## disks, "arit! distrib%tion e#i$inates sing#e write bott#eneck o0erhead for "arit! ca#c%#ation on write s%""#e$ented with "ara##e# $icro"rocessors or caching. 85) What is NAS in detail ? NAS or Network Attached Storage JNAS is %sed to refer to storage e#e$ents that connect to a network and "ro0ide fi#e access ser0ices to co$"%ter s!ste$s. Abbre0iated NAS. A NAS Storage E#e$ent
consists of an interface or engine, which i$"#e$ents the fi#e ser0ices, and one or $ore de0ices, on which data is stored. NAS e#e$ents $a! be attached to an! t!"e of network. When attached to SANs, NAS e#e$ents $a! be considered to be $e$bers of the SAS 8SAN Attached Storage) c#ass of storage e#e$ents. A c#ass of s!ste$s that "ro0ide fi#e ser0ices to host co$"%ters. A host s!ste$ that %ses network attached storage %ses a fi#e s!ste$ de0ice dri0er to access data %sing fi#e access "rotoco#s s%ch as NFS or '&FS. NAS s!ste$s inter"ret these co$$ands and "erfor$ the interna# fi#e and de0ice &/* o"erations necessar! to e.ec%te the$.K Tho%gh the NAS does s"eed %" b%#k transfers, it does not off#oad the 9AN #ike a SAN does. 3ost storage de0ices cannot Q%st "#%g into gigabit Ethernet and be shared this reE%ires a s"ecia#iHed fi#e ser0er the 0ariet! of s%""orted de0ices is $ore #i$ited.NAS has 0ario%s "rotoco#s estab#ished for s%ch needed feat%res as disco0er!, access contro#, and na$e ser0ices. 86)Briefly list the advantages of SAN ? SANs f%##! e."#oit high-"erfor$ance, highconnecti0it! network techno#ogies SANs e."and easi#! to kee" "ace with fast growing storage needs SANs a##ow an! ser0er to access an! data SANs he#" centra#iHe $anage$ent of storage reso%rces SANs red%ce tota# cost of ownershi" 8T'*) So$e $ore FAFs 1)What is the $ost critica# co$"onent in SAN? )What is the defa%#t id for S'S& <)A? -)What is "ara##e#is$? 5)What do !o% know abo%t SAN testing? 6)E."#ain a t!"ica# SAN #andsca"e? 1)What is fan-in and fan-o%t in SAN 2irt%a#iHation s!ste$? >)<ow is the intero"erabi#it! between the ser0er and the storage is achie0ed? ?)What are the "erfor$ance $etrics of SAN? A)What do !o% know abo%t &/* $eters , their t!"es and how are the %sed? 1:)What is the eE%i0a#ent of Address reso#%tion "rotoco# in storage? 11)What is $eant b! a0ai#abi#it! I re#iabi#it! in Storage ? 1 )What is +isaster 7eco0er! I how it is i$"#e$ented in a Storage en0iron$ent? 1-)E.a$"#e for fai#o0er c#%ster config%rations ? 15)What are the needs/ad0antages of Storage conso#idation ?
