16119 - Get to Know Your Data Sets

8/10/2019 16119 - Get to Know Your Data Sets

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DFSMS Basics:Data Set FundamentalsGet to Know Your Data Sets!Neal Bohling and Tom ReedDFSMS Defect Support @ IBM

August 7, !"#

Session Num$er "%""&



What's your experience level?What's your experience level?

IBM 7!&#"&%'

('!!)*+



Background

To full understand +-.S Data Sets,let/s loo0 at ho1 data is stored

Tape2Se3uential4

Dis02Direct4



DASD Structure

Modern De5ices are Modeled after this architecture6 " Trac0 '%%%# B tes " 8 linder "' Trac0s

Modern De5ices are Modeled after this architecture6 " Trac0 '%%%# B tes " 8 linder "' Trac0s



Data Sets

9 :olumes pro5ide a stream of data;

9 <e can reference $ 5arious methods;;= DASD $ 88**RR = 8 linder, *ead, Record= Relati5e Trac0 2con5erts to 8 l, *ead4= Relati5e B te 21hich con5erts to 88**RR4

9 But 1here do files $egin and end>

110010011100001011010100110010011110001011100011110010001100010111000010110001011110001011100011110000111101011011010100101011111100100111000111100100111010101110001111100001111010110110101001101011111000001110101011110100011001001110000101010100110010011110001011100011110010001100010111000010110001011110001011100011110000111101011011010100110101111110010011000111100100111010101110001111100001111010110110101001101011111000001110101011110100011001001110000101101010011001001111001011100011110010001100010111000010110001011110001011100011110000111101011011010100110101111110010011100011110010011101101110001111100001111010110110101001101011111000001110101011110100011001001110000101101010011001001111000101110001111001001100010111000010110001011110001011100011110000111101011011010100110101111110010011100011110010011101010111000111110000111010110110101001101011111000001110101011110100011001001110000101101010011001001111000101110001111001000110001011100001



Volume Table o ontents9 A Volume is a logicall defined dis0 or tape

= 8an $e a real dis0= ?suall is a 5irtual dis0

9 Volume "abel 2at 8 l!,Tr0!4= oints to :T.8

9 Volume Table o ontents 2:T.84= 8omprised of DS8Bs

9 "! t pes = Format ! &9 For more info, chec0 out

DFSMSdfp Ad5anced Ser5ices6https6--i$m;$i+-BdF#&T

= Maps out the entire dri5e9 Dri5e info 2FMT#49 Free space 2FMT'-749 Data sets 2FMT"- -C4

9 No1 1e can find an data set on the 5olume

https://ibm.biz/BdF49T

https://ibm.biz/BdF49T



Data Set #ames

9 Rules6= ?p to 3ualifiers, each at least " character long= ualifiers separated $ period 2;4

= ?p to ## total characters long= First character must $e A E or National 2 ,G,@4= Remaining can $e alphanumeric, national, or h phens

SHS"; R.8 IB; BA8)? "

*nd e5el ualifier



atalog

9A catalog is a data set that0eeps trac0 of other data sets

9 Ties DSN to :olume9 Managed $ the

8ATA .J address space

9 Includes MASTKR and?SKR catalogs

9 No1 1e can find andata set in the s stem

9 <ith shared catalogs,an data set in the pleL

Master 8atalog

Re3uest to find DS

8atalog rogram - ASID

:olume

Data Set



Data Set $rgani%ation

Data sets are still ust streams of $ tes 1ith no structure;Finding information 1ithin that stream is difficult;

Solution: Data Set $rgani%ation

Defines ho1 the data set is structured internall ;;T1o Main T pes, 1ith su$ t pes

#on&VSAM VSAM

DirectSe3uential

artitioned

)SDSKSDS

inear

RRDS



Blocking

9 Data Streams are logicall di5ided into B .8)S 1hich are further di5ided into RK8.RDS9 This is to reduce the num$er of I-.s

9 Trac0 ength6 set $ de5ice 2CC&! is '%%%# $ tes-trac049 Bloc0 Si+e 2B )SIEK46 Set $ user or calculated automaticall9 Record Si+e 2 RK8 46 Set $ the user

Data Stream on a disk '( track)

Bloc0 " Bloc0

Record " Record Record C Record #



#on&VSAM#on&VSAMDirect and Se*uential



Direct $rgani%ation

9Bloc0s are arranged $ their control num$er9 No records, $loc0s are organi+ed $ the application

9 Accessed 5ia the BDAM access method9 <or0s li0e a hashta$le = space is di5ided into e5en $loc0s9 Because not e5er entr ma $e used, some space ma $e 1asted;9 Reads and 1rites are for 1hole $loc0s at a time

8.NTR. B .8) B )SIEKO

" DATASTRINJ .NK,

empt O

C IN A JA APH FAR, FAR A<AH

# #



Se*uential $rgani%ation

9 .ne of the most common organi+ations ou/ll see9 Data is split into $loc0s, 1hich are split into records9 Records are arranged in the order the are 1ritten9 To add ne1 records, ou either6

= Re1rite the 1hole file= Add to the end

9 Accessed 5ia the BSAM or SAM access method9 Also comes in ARJK and KPTKNDKD formats

Bloc0 " Bloc0 Bloc0 C Bloc0 #



+artitioned Data Sets '+DS)

9 Data is di5ided up into mem$ers9 Mem$ers are stored se3uentiall9 Mem$ers ha5e uni3ue names 2" characters49 Director Kntries at the $eginning of the data set

lin0s mem$er names to data locationsDirector Data

MKMBKR"

MKMBKR

MKMBKRC

MKMBKR#

Mem$er Data " M

Mem$er Data 2cont4 Mem$er Data C

MC Mem$er Data #



+DS "imitations

9 imited to one 5olume9 rone to fragmentation6

= <hen a mem$er is deleted, the director entr is remo5ed,$ut the space remains unused leading to fragmentation

= Adding records to a mem$er remo5e the old mem$er and re 1rites it at the end= Adding ne1 mem$ers add to the end

9 K5entuall , a RK.RJ is needed to re$uild the data setand reclaim space

9 Sharing can cause pro$lems6= .nl one user can update at a time, $ut not enforced



+DS ,-tended '+DS,)

9 .orks relati/el0 interc1angeabl0 wit1 +DS9 Internal structure is different9 Ad5antages6

= 8an reuse space 2no more fragmentation4

= 8an eLtend as needed 2still limited to one 5olume4= Director is indeLed, lo1ering see0 time= Mem$ers can $e shared

9 8an store program o$ ects or data, $ut not $oth

9 8omes in :ersion" and :ersion9 For more information, see Tom/s presentations6= "%" %6 DSK Best ractices 2Monda 4= "%" 76 DSK :ersion Mem$er Jenerations 2<ed4



Generation Data Grou2s

9 Not a data set organi+ation, $ut a catalog construct9 Jroups of data sets organi+ed $ num$er 2J!!!!:!!49 Allo1s eas trac0ing of multiple generations-5ersion9 Must $e non :SAM, and must $e 8ATA .Jed

MH;DATA;J!!!':!!MH;DATA;J!!!#:!!MH;DATA;J!!!C:!!MH;DATA;J!!! :!!

MH;DATA;J!!!":!!MH;DATA;J!!!!:!!

JDJ6 MH;DATA8urrent entr 2#4

MH;DATA2Q"4

MH;DATA2 4



VSAMVSAMVirtual Se*uential Access Met1od



Virtual Se*uential Access Met1od 'VSAM)

9 Four su$ t pes6= )e Se3uenced Data Sets 2 KSDS 4= Kntr Se3uenced Data Sets 2 ,SDS 4= Relati5e Record Data Sets 2 33DS 4

= inear Data Sets 2 "DS 49 Instead of $loc0s, :SAM uses 8ontrol Inter5als and Areas

Track

8ontrol Inter5al 28I4 8ontrol Inter5al 28I4

Record " Record Record C Record #

ontrol Area ' A)



S21ereluster 2MH;8 ?STKR4

VSAM Terms

IndeL 8omponent 2;INDKP4

Data 8omponent 2;DATA4

luster

IndeL 8omponent

Data 8omponent A l t e r n a

t e 4 n d e -



KSDS 4nde- Structure

8I" C "!

8I " C 8IC ' 7 "! 8I# " "'

Data 4 '5ig1 Ke0 () Data 4 '5K 6) Data 4 '5K 7) Data 4 '5K8)

Data 4 '5K9) Data 4 '5K( ) Data 4 Data 4

INDEX DATA

T w o

4 n d e -

" e / e l s

Se*uence Set



Alternate 4nde-es

BOHLING........NEAL.........95116.......BANKACCOUNT.......

INDKP DATA

B.* INJ;;;;;;; 8I "

8I

8I C

8I #

8I '

K,Y

B.* INJ;;;;NKA ;;;

A4; K,Y

INDKP DATA

&'""% 8I "

8I B.* INJ

A4;

"ooku2

<se ke0

or 4nde-Searc1



VSAM S2lits

9 Split is 1hen an INSKRT 1on/t fit in a 8I9 A$out half of the data is mo5ed to a ne1 8I

8I" C "! #!"'Insert

8I" C "! 8I" #!"'

SPLIT



,ntr0 Se*uenced Data Set

9 No INDKP9 Records in order the 1ere added9 Al1a s add to the end

= No such thing as delete , onl flagged inacti5e

= Kmpt spaces can ne5er $e used9 Access se3uentiall , or directl using RBA9 Hou can use an AIP to lin0 0e s to RBA9 Jood for logs, $an0 transaction histor , etc



3elati/e 3ecord Data Set

9 re formatted fiLed length records= Se3uenced $ relati5e num$er= Slots can $e used or unused 2ma ha5e high fragmentation4= Insert and access are $ RRN 2relati5e record num$er4

= Allo1s direct and se3uential access= Thin0 *ash ta$le



Variable 3elati/e 3ecord Data Set

9 Similar to RRDS, $ut uses 5aria$le length records9 Records are stored in relati5e num$er order9 Similar to a )SDS6

= *as an indeL that correspond RRN to RBA 288**4

= ?ses S ITs 1hen insertingINDKP 8I

RRN" Record "

Record Record C

Record # deletedO Record '

RRN

RRNC

RRN#

RRN'



"inear Data Set

9 B te addressa$le storage 2JKT $ te "'%7#49 8I Si+e is multiple of #!&%9 Kssentiall , a non :SAM file 1ith :SAM facilities9 Allo1s Data In :irtual

= Reads a #0 page into storage= ets the program access it as if it 1ere memor



5FS and %=FS

9 *FS *ierarchical File S stem= ?sed $ ?NIP to store director structures= Single 5olume se3uential data= From +-.S, it loo0s similar to a DS= ?niL s stem mounts them = thin0 IS. file

9 E-FS = Ne1er 5ersion of *FS 2+-.S ";74= Better performance= ?ses :SAM inear DS

9 References6= z/OS Unix System Service Planning, https6--i$m;$i+-BdF#C5= DFS S Using Data Sets, https6--i$m;$i+-BdF#Cm



ommon <sesTY+, ommon <se

Direct Data, not that common

Se3uential K5er thing = logs, KRK, notes

DS .AD IBs, 8 collections, 8 IST li$raries

DSK Same as DS

)SDS DATA, such as $an0 recordsKSDS Transaction logs

RRDS Data

inear DB ta$les, SMS S8DS

*FS-+FS ?niL director structures

https://ibm.biz/BdF43m

https://ibm.biz/BdF43v



"imitations

9 All format ha5e limitations6"imitation Direct=Se* VSAM +DS +DS, <ni-

MaL Si+e %','C' trac0s #JB %','C' TR)

MaL KLtents "%-5ol " C- '' "% " C " C- ''

MaL :olumes '& '& " " "

Sharing Integ No Some No Some No

Fragmentation Hes-No Hes Hes Hes No



,-tended Format

9KLtended Format relie5es some of the limitations9 ogicall the same format

9 Stored differentl on the hard1are to eLploit hard1are andsoft1are facilities of SMS

9 Must $e SMS managed9 Kna$led through allocation or data class parameter

9 Allo1s some eLtra features6

= 8ompression= Data Striping= KLtended Addressing 2larger files4= :SAM Allocation and Buffering



,-tended Format Features

9 om2ression:= Reduces space to store data= Kna$led 5ia Data 8lass compaction attri$ute= <or0s 1ith Se3uential and )SDS

= Session "%"C!, "%"C , "'7!& all tal0 more a$out it9 Stri2ing:

= Distri$utes Data $loc0s across multiple 5olumes= Allo1s higher throughput rate

= <or0s 1ith :SAM and Se3uential data sets= 8ontrolled $ storage class parameters



,-tended Format Features

9 ,-tended Addressing:= :SAM can gro1 to #JB U 8I Si+e 2" TB for C ) 8I4= Se3uential DS can ha5e " C eLtends per 5ol o5er '& 5ols= DS, DSK, Direct do not change

9 VSAM Allocation = Bu ering= artial Release= S stem Managed Buffering

= Note6 8atalogs cannot $e eLtended format



reating Data Setsarameter Definitions



De ining Data Set Attributes

9 Defining Non :SAM= > "= IS F anels

= D namic Allocation

9 Defining :SAM= 4D AMS= 8

= D namic Allocation

Parameter are roughly the same !et"een utilities#We'll focus on the Attribute



Data Set Attributes

9S2ace <nits= Defines 1hich construct ou/ll use to allocate space= ossi$le 5alues6

9 8H = c linders 2 "' trac0s, ( C!)B49 TR) = trac0s 2 '%,%%# $ tes49 B )S = $loc0s9 )B, MB, BHTKS9 Records

9 A/erage 3ecord <nit 'AVG3, )

= ?sed primaril in Data 8lass= Defines a multiple for rimar and Secondar space= ossi$le 5alues6 ? 2unit4, ) 2"! #4, M 2"!# '%4



Data Set Attributes

9 Space attri$ute eLample 2 8 46

S A8K 2TR),2'!,C,"!!4,R SK4

<nits +rimar0

Secondar0

Director0Blocks



#on&VSAM Attributes

9 Data Set $rgani%ation 'DS$3G)= S = h sical Se3uential= . = artitioned= DA = Direct= For a$solute addressing, add a ? , such as S?

9 3ecord Format '3, FM)= Specifies characteristics of the records

= KLample6 FB, :B, :BS, ?

B0te ( B0te 6

F = FiLed ength B = Bloc0ed Records

: = :aria$le ength S = Spanned Records? = ?ndefined length BS = Bloc0ed Spanned



Data Set Attributes

9"ogical 3ecord "engt1 '"3, "=3, $3DS4?,)= Specifies the length, in $ tes, of the records= If 5aria$le length 2:B4, specifies the maLimum length= *as no effect for RK8FM ?

9 Block Si%e 'B"KS4?,)= Defines the si+e of the $loc0s to $e used= Specif ! to use S stem Determined Bloc0 Si+e

= Must $e a multiple of RK8



#on&VSAM Attributes

9Data Set T02e 'DS#TY+,)= Defines the t pe of data set ou are creating= ossi$le 5alues6

9 IBRARH = artitioned Data Set KLtended 2 DSK49 DS = artitioned Data Set9 *FS = *ierarchical File S stem9 ARJK = 8reates a large format se3uential9 KPTRK = KLtended format, re3uired9 KPT RKF = KLtended format, preferred9 BASI8 = Basic format se3uential9 Blan0 = Se3uential or DS, depending on Director field

= DSNTH K relies on other parms, and does not o5erride



VSAM Attributes

93, $3DS4?,= Same as RK8= Defines the si+e of the records

9 $#T3$"4#T,3VA"S4?,

= Defines the 8I Si+e= Similar to B )SIEK

9 F3,,S+A ,= Defines ho1 much space is left in the 8I for insert-eLpansion

9 S+A##,D=#$#S+A##,D= Defines 1hether records are spanned 2similar to S in FBS4



VSAM Attributes

9K,YS 2length offset4= Defines the length and offset of the :SAM 0e for )SDS= KLample6 )KHS2"#,!4

= KLample 6 )KHS2', 4


K,Y


K,Y



VSAM Attributes

9 4#D,;,D = "4#,A3 = #$#4#D,;,D = #<MB,3,D:= )e 1ord that defines the :SAM file t pe= INDKPKD = )DSD

= INKAR = linear= N.NINDKPKD = KSDS= N?MBKRKD = RRDS

9 Man , man more;;;= See DFS S $ccess etho% Services &omman%s

2S8 C % #% !"4



,-am2les o Data Set De initions

9 8 DD 8ard6//OUTFILE DD DSN=SYS1.TRACE.T,

// SPACE=(CYL,(50,3 ,RLSE ,DISP=(,CATLG,DELETE ,

// LRECL=10!",BLKSI#E=61"",RECF$=FB,DSORG=PS,

// UNIT=3390,%OL=SER=DU$PD1

9 ID8AMS StatementsDEFINE CLUSTER( NA$E($Y.%SA$.FILE &

CYLINDERS(10 5 INDE'ED %OLU$ES( &

RECORDSI#E(10!" 10!" KEYS(16 0

CONTROLINTER%ALSI#E(3!)6* &

INDE'( NA$E($Y.%SA$.FILE.INDE' &

DATA( NA$E($Y.%SA$.FILE.DATA



<tilities and Subs0stemsIntro to Managing Data



<tilities

9 ID8AMS= <or0s 1ith :SAM data sets= 8an do define, cop , delete= Also interacts 1ith catalog information

9 IKB8. H= 8op DS and DSK= 8on5ert $et1een DS and DSK

9 IKBJKNKR

= 8op se3uential files9 IKFBR"#

= Does nothing, $ut can use DD cards to manage data sets



<tilities

9 DFSMSdss 2DSS4= :er po1erful data mo5ement tool= Does cop - $ac0up - data con5ersion

9 IS F .ption C panels= anel dri5en utilities to create - delete - manage data sets= Also has an editor that can edit se3uential data sets

9 ISMF Data Set anels= Allo1s edit - delete - rename - etc= Allo1s ou to sa5e data sets lists



4ntroduction to Managing Data

9 Storage Management Su$s stem 2SMS4= Runs under the SMS ASID= *elps storage administrators manage data sets= Includes classes to simplif allocation and define attri$utes6

9 DATA 8 ASS = defines 8 parms for default use9 ST.RAJK 8 ASS = defines accessi$ilit and performance

re3uirements9 MANAJKMKNT 8 ASS = defines retention and management9 ST.RAJK JR.? = defines 1hich group of 5olumes

= Automatic 8lass Selection 2A8S4 routines assign classes$ased on user 1ritten logic9 &ome to session ( ) *or +an% On $&S "riting -Fri . a0

= SMS managed has a storage class assigned



Subs0stems ontinued

9 SMS+DS, = SMS+DS,(= Address spaces needed to use DSK= Manage seriali+ation on DSK across the pleL= Kna$les s stem 1ide $uffering= See sessions "%" % 2Monda @ #6"'4 for further info

9 SMSVSAM= Kna$les :SAM Record e5el Sharing= Kna$les cross pleL seriali+ation at the record le5el

= Also has enhanced $uffering and caching capa$ilities= Not re3uired for :SAM, $ut has $enefits in cross pleL en5ironments= See sessions "%" # and "%" ' 2Mon-Tues4 for more info



Summar0

9 T1o $asic t pes of data sets = :SAM - N.N :SAM9 Man su$ 5arieties

= DS- DSK= Se3uential-Direct

= FiLed-:aria$le-Spanned Bloc09 Data set attri$utes define t pe and options9 Attri$utes reflect de5ices and format9 There are se5eral utilities to help create - manage data

9 Se5eral su$s stems can $e ena$led to assist and ena$leadditional features



DFSMS Basics:Data Set FundamentalsGet to Know Your Data Sets!Neal Bohling and Tom ReedDFSMS Defect Support @ IBM

August 7, !"#

Session Num$er "%""&



#otices @ Disclaimers8op right V !"# $ International Business Machines 8orporation;

No part of this document ma $e reproduced or transmitted in an form 1ithout 1ritten permission from IBM 8orporation;

roduct information and data has $een re5ie1ed for accurac as of the date of initial pu$lication; roduct information and data issu$ ect to change 1ithout notice; This document could include technical inaccuracies or t pographical errors; IBM ma ma0eimpro5ements and-or changes in the products and-or programs descri$ed herein at an time 1ithout notice;

References in this document to IBM products, programs, or ser5ices does not impl that IBM intends to ma0e such products,programs or ser5ices a5aila$le in all countries in 1hich IBM operates or does $usiness; 8onsult our local IBM representati5e orIBM Business artner for information a$out the product and ser5ices a5aila$le in our area;

An reference to an IBM rogram roduct in this document is not intended to state or impl that onl that program product ma $eused; An functionall e3ui5alent program, that does not infringe IBM/s intellectuall propert rights, ma $e used instead; It is theuser/s responsi$ilit to e5aluate and 5erif the operation of an non IBM product, program or ser5ice;

T*K INF.RMATI.N R.:IDKD IN T*IS D.8?MKNT IS DISTRIB?TKD WAS ISW<IT*.?T ANH <ARRANTH, KIT*KR KP RKSS.R IM IKD; IBM KP RKSS H DIS8 AIMS ANH <ARRANTIKS .F MKR8*ANTABI ITH, FITNKSS F.R A ARTI8? AR?R .SK .R INFRINJKMKNT; IBM shall ha5e no responsi$ilit to update this information; IBM products are 1arranted accordingto the terms and conditions of the agreements 2e;g;, IBM 8ustomer Agreement, Statement of imited <arrant, Internationalrogram icense Agreement, etc;4 under 1hich the are pro5ided; IBM is not responsi$le for the performance or interopera$ilit ofan non IBM products discussed herein;



#otices @ Disclaimers

The performance data contained herein 1as o$tained in a controlled, isolated en5ironment; Actual results that ma $e o$tained inother operating en5ironments ma 5ar significantl ; <hile IBM has re5ie1ed each item for accurac in a specific situation, there isno guarantee that the same or similar results 1ill $e o$tained else1here;

The responsi$ilit for use of this information or the implementation of an of these techni3ues is a customer responsi$ilit anddepends on the customer/s or user/s a$ilit to e5aluate and integrate them into their operating en5ironment; 8ustomers or usersattempting to adapt these techni3ues to their o1n en5ironments do so at their o1n ris0; IN N. K:KNT S*A IBM BK IAB KF.R ANH DAMAJK ARISINJ FR.M T*K ?SK .F T*IS INF.RMATI.N, IN8 ?DINJ B?T N.T IMITKD T.,.SS .F DATA, B?SINKSS INTKRR? TI.N, .SS .F R.FIT .R .SS .F . .RT?NITH;

Information concerning non IBM products 1as o$tained from the suppliers of those products, their pu$lished announcements orother pu$licl a5aila$le sources; IBM has not necessaril tested those products in connection 1ith this pu$lication and cannotconfirm the accurac of performance, compati$ilit or another claims related to non IBM products; uestions on the capa$ilities ofnon IBM products should $e addressed to the suppliers of those products;

The pro5ision of the information contained herein is not intended to, and does not, grant an right or license under an IBM patentsor cop rights; In3uiries regarding patent or cop right licenses should $e made, in 1riting, to6

IBM Director of icensingIBM 8orporationNorth 8astle Dri5eArmon0, NH "!'!# "7 '?;S;A;

An statements regarding IBM/s future direction and intent are su$ ect to change or 1ithdra1al 1ithout notice, and represent goalsand o$ ecti5es onl ;



TrademarksDFSMSdfp, DFSMSdss, DFSMShsm, DFSMSrmm, IBM, IMS, M:S, M:S-DF , M:S-KSA, M:S-S , M:S-PA,

.S-C&!, SANerg , and S are trademar0s of International Business Machines 8orporation in the ?nited States,other countries, or $oth;

AIP, 8I8S, DB , DFSMS-M:S, arallel S spleL, .S-C&!, S-C&!, Seascape, and +-.S are registered trademar0sof International Business Machines 8orporation in the ?nited States, other countries, or $oth;

Domino, otus, otus Notes, Notes, and SmartSuite are trademar0s or registered trademar0s of otusDe5elopment 8orporation; Ti5oli, TMK, Ti5oli Knterprise are trademar0s of Ti5oli S stems Inc; in the ?nitedStates and-or other countries;

a5a and all a5a $ased trademar0s are trademar0s of Sun Micros stems, Inc; in the ?nited States, othercountries, or $oth; ?NIP is a registered trademar0 in the ?nited States and other countries licensed eLclusi5elthrough The .pen Jroup;

.ther compan , product, and ser5ice names ma $e trademar0s or ser5ice mar0s of others;

16119 - Get to Know Your Data Sets

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