Sun Microsystems Virtual Tape Library User manual

Submit comments about this document at: [email protected]

Sun Microsystems, Inc.

www.sun.com

Virtual Tape Library

VTL User Guide

Part No. 96267

May 2008, Revision G

Sun Microsystems, Inc. has intellectual property rights relating to technology that is described in this document. In particular, and without

limitation, these intellectual property rights may include one or more of the U.S. patents listed at http://www.sun.com/patents and one or

more additional patents or pending patent applications in the U.S. and in other countries.

This document and the product to which it pertains are distributed under licenses restricting their use, copying, distribution, and

decompilation. No part of the product or of this document may be reproduced in any form by any means without prior written authorization of

Sun and its licensors, if any.

Third-party software, including font technology, is copyrighted and licensed from Sun suppliers.

Parts of the product may be derived from Berkeley BSD systems, licensed from the University of California. UNIX is a registered trademark in

the U.S. and in other countries, exclusively licensed through X/Open Company, Ltd.

Sun, Sun Microsystems, the Sun logo, Java, AnswerBook2, docs.sun.com, and Solaris are trademarks or registered trademarks of Sun

Microsystems, Inc. in the U.S. and in other countries.

AMD Opteron is a trademark or registered trademark of Advanced Microdevices, Inc.

All SPARC trademarks are used under license and are trademarks or registered trademarks of SPARC International, Inc. in the U.S. and in other

countries. Products bearing SPARC trademarks are based upon an architecture developed by Sun Microsystems, Inc.

The OPEN LOOK and Sun™ Graphical User Interface was developed by Sun Microsystems, Inc. for its users and licensees. Sun acknowledges

the pioneering efforts of Xerox in researching and developing the concept of visual or graphical user interfaces for the computer industry. Sun

holds a non-exclusive license from Xerox to the Xerox Graphical User Interface, which license also covers Sun’s licensees who implement OPEN

LOOK GUIs and otherwise comply with Sun’s written license agreements.

U.S. Government Rights—Commercial use. Government users are subject to the Sun Microsystems, Inc. standard license agreement and

applicable provisions of the FAR and its supplements.

DOCUMENTATION IS PROVIDED "AS IS" AND ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,

INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT,

ARE DISCLAIMED, EXCEPT TO THE EXTENT THAT SUCH DISCLAIMERS ARE HELD TO BE LEGALLY INVALID.

Sun Microsystems, Inc. a les droits de propriété intellectuels relatants à la technologie qui est décrit dans ce document. En particulier, et sans la

limitation, ces droits de propriété intellectuels peuvent inclure un ou plus des brevets américains énumérés à http://www.sun.com/patents et

un ou les brevets plus supplémentaires ou les applications de brevet en attente dans les Etats-Unis et dans les autres pays.

Ce produit ou document est protégé par un copyright et distribué avec des licences qui en restreignent l’utilisation, la copie, la distribution, et la

décompilation. Aucune partie de ce produit ou document ne peut être reproduite sous aucune forme, par quelque moyen que ce soit, sans

l’autorisation préalable et écrite de Sun et de ses bailleurs de licence, s’il y en a.

Le logiciel détenu par des tiers, et qui comprend la technologie relative aux polices de caractères, est protégé par un copyright et licencié par des

fournisseurs de Sun.

Des parties de ce produit pourront être dérivées des systèmes Berkeley BSD licenciés par l’Université de Californie. UNIX est une marque

déposée aux Etats-Unis et dans d’autres pays et licenciée exclusivement par X/Open Company, Ltd.

Sun, Sun Microsystems, le logo Sun, Java, AnswerBook2, docs.sun.com, et Solaris sont des marques de fabrique ou des marques déposées de

Sun Microsystems, Inc. aux Etats-Unis et dans d’autres pays.

AMD Opteron est une marque de fabrique ou une marque deposee de Advanced Microdevices, Inc.

Toutes les marques SPARC sont utilisées sous licence et sont des marques de fabrique ou des marques déposées de SPARC International, Inc.

aux Etats-Unis et dans d’autres pays. Les produits portant les marques SPARC sont basés sur une architecture développée par Sun

Microsystems, Inc.

L’interface d’utilisation graphique OPEN LOOK et Sun™ a été développée par Sun Microsystems, Inc. pour ses utilisateurs et licenciés. Sun

reconnaît les efforts de pionniers de Xerox pour la recherche et le développement du concept des interfaces d’utilisation visuelle ou graphique

pour l’industrie de l’informatique. Sun détient une license non exclusive de Xerox sur l’interface d’utilisation graphique Xerox, cette licence

couvrant également les licenciées de Sun qui mettent en place l’interface d ’utilisation graphique OPEN LOOK et qui en outre se conforment aux

licences écrites de Sun.

LA DOCUMENTATION EST FOURNIE "EN L’ÉTAT" ET TOUTES AUTRES CONDITIONS, DECLARATIONS ET GARANTIES EXPRESSES

OU TACITES SONT FORMELLEMENT EXCLUES, DANS LA MESURE AUTORISEE PAR LA LOI APPLICABLE, Y COMPRIS NOTAMMENT

TOUTE GARANTIE IMPLICITE RELATIVE A LA QUALITE MARCHANDE, A L’APTITUDE A UNE UTILISATION PARTICULIERE OU A

L’ABSENCE DE CONTREFAÇON.

96267 • G iii

Revision History

Short Name Part # Revision Date Comments

VTL User Guide 96267 Nov 2006 Base document supplied by the

vendor.

A Jan 2007 Major revision.

B Mar 2007 Published. EC 131376.

C Aug 2007 Major revision.

D Nov 2007 Minor revision.

E Feb 2008 Major revision to cover VTL Plus 2.0

F Mar 2008 Major revision to the commandline

appendix

G May 2008 Revised for VTL Plus 2.0 Update 1.

iv VTL User Guide • May 2008 G • 96267

96267 • G v

Contents

About this book xi

1. Introductio n:VTLappliancesand enterprisedata‐protect ion 1

Features 2

AdvantagesofVTLtape virtualization 4

Shorterruntimes andreduceddependencyonbackupwindows 4

Shorterruntimesfornon ‐sequentialbackupjobs 5

Improvedreliability 5

Betterutilizationoftapesubsystems 5

Improvedutilizationofbackupmedia 6

Larger,moreflexiblelibraries 6

CompatibilitywithACSLSmanagementsoftware 6

Truetapevirtualizationwithdynamically

allocateddiskspace 7

KeyVT L featuresandoptions 8

NDMPmigration 8

VTLhigh‐availabilityoption 9

AutomatedTapeCach ing 12

Virtualtapereplication 12

VTLSecureTapeen cryptio noption 14

vi VTL User Guide • May 2008 G • 96267

2. UnderstandingVTLZoning 15

Zoningforstandard‐availabilitysystems 15

Zoningforhigh‐availabilitysystems 16

3. UsingtheVTLconsole 19

RunningtheVTLconsoleapplication 20

Populatingthec ons ole 20

UnderstandingtheVTLcons oleinterface 22

VirtualTapeLibrarySystem 24

SANClien ts 25

Reports 25

PhysicalResources 26

4. VTLoper ation s 27

Managingnetworkconnectivity 27

Managingvirtuallibraries 33

Configuringphysicallibrari esandde vices 34

Configuringandprovis ioningvirtuallibraries 39

Creatingvirtual

tapes 56

Connectingvirtuallibrarieswithstorageclients 64

ControllingVTL virtuallibraries withACSLS 70

Backingupthe VTLsystemconfiguration 75

Recoveringthese rverconfiguration 79

ProtectingVTLmetadata 79

Administeringuseracountsandpasswords 82

Virtualtapedrivecompression 84

Managingtapes 86

Locatingvirtualtapes 86

Replicatingtapes 86

96267 • G Contents vii

Copyingtapes 104

Movingtapesbetweenvirtualandphysicallibraries 107

Managingtapecach ing 120

Creatingandviewingreports 123

Encryptingandshreddi ng data 127

WorkingwiththeEventLog 135

UsingtheAttentionRequiredtab 138

ManagingVTLservers 140

5. Instal ling theVTLconsole 143

6. Recoveryfollowingasystemfailure 147

Failback 147

Resumingbackupsfollowingafailover/failback 157

7. Configuringemail alerts 159

8. UpdatingVTLsoftware 165

A. VT Lcomm andline

reference 169

Usingthecommandlineutility 169

Commands 169

Commonarguments 170

Login/logouttothe VTLServer 171

LogintotheVTLServer 171

LogoutfromtheVTLServer 172

Virtualdevice s/Cl ient s 172

Getvirtualdevicelist 172

GetClientvirtualdevicelist 173

Addclient 174

Deleteclient 174

viii VTL User Guide • May 2008 G • 96267

Getclientproperties 175

Assignvirtualdevice 175

Unassignvirtual device 176

Createvirtualdevice 177

Deletevirtualdevice 177

Getsupportedvirtuallibraries 178

Getsupportedvirtualdrives 179

Createvirtualtapelibrary 179

Addvirtualtapedrive 181

Createstandalonetapedrive 182

Createvirtualtape 183

Movevirtualtape 184

Tapecopy 186

Settapeduplication 186

Settapeproperties 187

Automatedtapecaching 189

Settapecaching 189

Syncphysicaltapes 191

Migratevirtual

tapes 192

Reclaimdiskspace 193

Renewcache 193

Systemconfiguration 194

Addalicensekeycode 194

Removealicensekeycode 195

GetVTLinfo 195

Import/Export 196

Importtape 196

Exportvirtualtape 197

96267 • G Contents ix

Getimport/exportjobstatus 198

Resumeimport/exportjobs 199

Deleteimport/exportjobs 200

Suspendimport/exportjobs 200

Cancelimport/exportjobs 200

Replication 201

Createarepli ca 201

Promoteareplica 203

Removereplication 203

Suspendreplication 204

Resumereplication 205

Setreplication properties 205

Getreplicationproperties 206

Getreplicationstatus 207

Startreplication 207

Stopreplication 208

Physicaldevices 208

Inventoryphysicaltapelibrary 208

Getphysicalta p elist 209

Movephysicaltape 209

Ejectphysicaltape 210

Assignphysicalresource

toVTL 211

Unassignphys icalresourcefromVTL 211

Getphysicaldeviceinformation 212

Rescanphysicaldevices 213

Importdisk 213

PreparephysicaldeviceforVTLserver 214

Reports 215

x VTL User Guide • May 2008 G • 96267

Serverthroughputreport 215

SCSIchannelthroughputreport 216

Devicethroughputreport 217

Physicalresourcesconfigurationreport 218

Diskusagereport 218

Physicalresourcesallocationrepor t 219

Specificphysicalresourceallocationreport 219

FibreChanneladapterconfigurationre por t 220

Replicationstatusreport 220

Virtuallibraryinformationrepor t 221

Virtualtapeinformationreport 222

Createjobrepo rt 223

EventLog 224

GetEventLog 224

Technicalsupport 225

GetX‐Ray 225

Getattentionre quiredinformation 226

B. R equ iredports 227

C. Troubleshooting 229

Problemsduringconsoleoperations 229

Problemsaffectingphysicalresources 232

Problemswithvi rtualresources 233

Problemsduringimport/exportoperations 237

TakinganX ‐rayfortech nicalsupport 239

D. SNM Ptraps 243

E. ILOMcommandreference 275

96267 • G xi

Aboutthisbook

Thisbookintroducestapevirtualizationandguidesyouthroughtheadministration

ofSunStorageTek VirtualTapeLibrary(VTL)solutions,includingVTLPlus2.0and

VTLValuesystems.It startswith ahigh‐levelexplanationofVTLtechnology,

commondeploymentarchitectures,andspecialfeatures.Itthenprovidesdetailed

instructionsforcarryingout

thetaskscommontoVTLadmini strati onaccordingto

SunVTLbest practices,including:

■ SANzoning

■ usingtheVTLConsolegraphicaluserinterface(GUI)andinstallingcopieson

managementstation s

■ administeringlocalareanetwork(LAN)connections

■ designing,creating,an dmanagingvirtuallibrari es andvirtualtapes

■ usingspecialfeatureslikeautomatictapecachi ng, automatictapearchiving,and

tapereplication

■ usingencryptionanddatacompressionfeaturesto bestadvantage

■ handlingfailbackafterahigh‐availabilitysystemhasfailedover

■ reporting

■ configurin g andusingemailnotifications

Finally,appendicesprovideadditionalinformationthat,while notesse nt ia ltoa

normalinstalla tion, mayproveusefulinspecialcircumstances. 

Thedocum entistask‐orien ted ,organizedaroundtheworkyouhavetodoratherthan

aroundthefeaturesorcomponentsoftheproduct.Eachchapterandsection

begins

withalist ofthetasksitcontains.Tasksarepresentedinorder,andthestepsineach 

processarenumbered,inthesequenceinwhichtheyaretobeperformed.

Conditionalsteps(stepsthatyouperformonlyinspecifiedcircumstances)begin

withthecondition(“IfA...”) and

endwiththecorrespondingaction(“...do B”); if

theconditiondoesnotapply,yousimplyskipthestep.Eachtaskendswitha

referencetothenexttaskin thesequence:

Nexttask:“Installing...” onpage 3.

xii VTL User Guide • May 2008 G • 96267

Whenthe setupprocessbranches,thetaskendswithconditionalalternatives:

Nexttask:

■ Ifthecustomerdoesnotplanto runthemanagementconsolefromahoston

thelocalareanetwork(LAN),pressSkip,andgotothenexttask.

■ Otherwise,carryouttheprocedure “Configuringthe EthernetLAN”on

page 57.

Whenyouhavefinishedasequenceoftasks,thisisclearlynoted:

Stop here.

Tominimizethetimeyouspendswitchingbetweenpublicationsorbet weenmajor

sectionsofthedocument,wehavemadeanefforttoavoidcrossreferencesto

externalinformation

whereverpossible.Ifyouneedtohaveafigure,atable,ora

procedure, itshouldalwaysbe,atworst,onaneighboringpage.

Takingadvantageofthisbook’shypertextfeatures

Ifyouchoosetoviewthisbookonline,ratherthaninprintedform,you canjump

quicklytoanypartofthebookbyclickingonthecorrespondingentryunderthe

BookmarkstabontheleftsideoftheAdobeAcrobatinterface.Inaddition,clicking

onentriesinthetableof

contents,crossreferences,orreferencestosubsequenttasks

willtakeyoudirectlytotheindicatedpartofthedocument.Youcanthenusethe

backarrowon theAdobeAcrobatReadertoreturn,ifdesired,tothepointyouleft.

Inaddition,clickingonmostUniformResourceLocators(URLs)and

onmost

referencestoonlineresourceswillopenyourdefaultwebbrowsertothe

correspondingwebpage,so thatyou can,ifnecessar y,obtainarequireddownload

immediately (beaware,however,URLstospecificpag es ch angefrequentlyandmay

notalwaysbeaccurate).

96267 • G About this book xiii

Understandingtheconventionsusedinthisbook

Thetablebelowillustratestheconventionsthatrepresentliteralandvariablevalues,

commands,andpropertynamesinthisbook.

Obtainingth elatestinformation andsupportingresources

TheSunStorageTekSupportportal<www.support.storagetek.com>provides

linkstothelatestdocumentation,softwareupdates,andlicensingresourcesforVTL

Plussolutions.Alwayschecktheportalforupdatestothisdocumentbefore

proceeding.DocumentsdistributedonCDROMmaynotreflectthelate stchangesto

VTLhardware,software,andservices.

Commentingonthisbook

Sunwelcomesyour commentsandsuggestionsforimprovingthisbook.Contactus

at[email protected]. Pleaseincludethetitle,partnumber,issuedate,andrevision:

VTL User Guide,partnumber96267(May2008Revision G).

Convention Meaning Examples

AaBbCc123 Fixed‐widthtextisusedfor literal values,

includin g namesofcommands,files,

directories,literalcomputerinputs/outputs,

andUniformResource Locators(URLs)

Edityour.loginfile.

Use ls -a tolistfiles.

% You have mail.

AaBbCc123

Obliquetextisused for variablesthatstand

forrealnamesorvaluesandfor booktitles.

Todeleteafile,

type:

rm

filename.

ABCD Bold,sa n‐seriftext indicate s calloutsin

illustr at ion s.

Click Submit (A below).

1. Numberedpa ragr aphs indicatest eps ina

processthatshouldbeexecutedinsequential

order.



■ Bulletedparagraphsindicatelistsof

alternativesorcomponents.

[

VTL_Plus]#acommandlinepr om p t

xiv VTL User Guide • May 2008 G • 96267

96267 • G 1

CHAPTER

1

Introduction:VTLappliancesand

enterprisedata‐protection

SunStorageTekVirtualTapeLibrary(VTL)technologymakesthebenefitsofdisk‐to‐

disk‐to‐tapearchitectureavailabletocomplex backupenvironmentsthatcannot 

readilyaccommodatethedisruptionsandadministrativeburdensthatoften

accompanymajorchangestoinformation‐managementenvironm entsandprocesses.

VTLsol uti ons makediskmediaavailabletoapplicationsthatare

configuredtowork

withtape.VTLsoftwarepresentsyourexistingtape‐centricbackuparchitecturewith

whatappeartobe familiar tapelibra rie s, drives,anddatacartridgeswhilemanaging

thecomplexitiesoftheimplementation—diskarrays,RAIDgroups,andlogical

volumes—internally.

Suchtransparencyisa bso lutely criticalwhenbackupisjustoneaspect

ofan

enterprise‐widebusiness‐continuityplan.Whenlegacysystemsand multiple,

interdependentapplications,procedures,policies,and/orserviceprovider sare

involved,evenmodestchangestoabackuparchitecturecan haveunforeseen,far‐

reachingconsequences.

Theadvantagesthatdisk‐to‐diskbackuphastoofferarenolesscriticalincomplex

environments.

Heavyworkloads,tightschedules,andmultipledependenciesoften

makebackupwindowsverytightornon‐existent.Jobsthatfailto completecannot,

inmostcases,beretried.Tape‐basedbackupsystemsperformwellwhenhandling

bigjobs,likefullbackupsoflargefilesandfilesystemsthat canstreamlarge

amountsofsequentialdata.Butmuchofthe currentbackupworkloadconsistsof

intermittent,essentiall y randomI/O—incrementals,fullbackupsofheterogeneous

smallserversandworkstations,andsmallfiles(suchas thoseassociatedwithemail

systems).Tapedrivesperformpoorlyundertheseconditions.Butdisk‐basedstorage

isideallyplacedtohandle

thistypeofI/O.

Theremainderofthischapterprovides:

■ abriefsummaryofVTL“Features”onpage 2

■ adetaileddiscussionofthe“A d v a n t a g e s ofVTLtapevirtualization”onpage 4

■ amorein‐depthlookatselected,“KeyVTLfeaturesandoptions”onpage 8.

Features

2 VTL User Guide • May 2008 G • 96267

Features

TheSunStorageTekVTLsolutionhasthefollowingfeatures:

■ Emulationofmostwidelyusedtapelibra rie s, drives,andmedia types,including

thelatestSunStorageTekT10000‐seriesdrivesan d media

■ Dynamicallocationofdiskcapacity

VTLsoftwarecanallocatediskspacetovirtualtapesin5‐GBincrements, upto

thefull,ratedcapacityoftheemulated media.Thisminimizeswastedspace,

providesnaturalloadbalancing,andoptimizestheperformanceofthediskarray.

■ AutoArchivefeature

TheAuto Archiveoptionwritesdatatoph ys i c altapewheneverabackup

applica ti o norutilitymovesavirtualtapefromavirtuallibrarytoan

import/exportslot.Thephys i cal tapelibrarymustsupportbarcodes:the VTL

softwarehastofindamatchingbarcodeinthephysicallibraryin

ordertoexport

avirtualtapetoaphysicalcartrid ge. 

■ ReplicationoftapestolocalandremoteVTLsystems

VTLsoftwaresupportsmanualcopyingandbothevent‐andpolicy‐driven

automaticreplicationmethods.

■ AutomatedTapeCachingoption

Withtheoptionaltape‐cachingfeature,VTLsoftwarecanautomaticallysavea

singlevirtualvolumewithasinglebarcodeintwophysical forms,oneondisk

andoneonphysicaltape .Thetape‐cachingfeaturemanagesretentionand

migrationofthephy si c al images,underthecontrolof

user‐specifiedpoliciesand

schedules.Thisletsuserskeepspaceinthediskcachefreefornewbackupsets

whilere tain ing thetapeimagesofoldervirtualvolumes.Whenavirtualvolume

nolongerresidesinthediskcache,apointerinthecacheseamlesslyredirects 

requeststothetapeimage.



■ Highavailabilityoption

Anoptional,hi gh ‐availabilityconfigurationprovidesintelligentfailover,with

duplicate,self‐monitoringVTLservernodesandredundant,primaryandst andby 

pathsbetweenbackupapplication sand VT Ldata.

■ Encryptionandsecuredatade struct ion

Toensurethatthedatathatyouexporttophysi cal tapeisconfidentialandse cu re,

VTLoffersaSecureTapeOptionthatusestheAdvancedEncryptionStandard

(AES)algorithmpublishedbytheNationalInstituteofSt an dards andTechnology,

anagencyoftheU.S.government.

Features

96267 • G Chapter 1 Introduction: VTL appliances and enterprise data-protection 3

TheShredfeatureinsuresmilitarystandard,securedatadestructionby

overwritingvirtualtapewithrandombitpatterns.Datadestructionjobsare

queuedsothattheshredprocessdoesnothaveanexcessiveimpactupon

performance.

■ Datacompression

SunVTLPlus2.0supportsbothsoftware‐basedandhardware‐baseddata

compression.

Bothdata‐compressiontechnologiesoffersimilarfunctionality.Botharebasedon

theLZOalgorithm.Whennecessary,eithercanincreasetheamountofdatathat

willfitonavirtualtapeofagivencapacity.Compressionratios

canapproach2:1

fordatasetsmadeupofhighlycompressib lefiletypes,suchasplaintextand

uncompressedbitmappedimages(incompressiblefiletypes,suchasZIParchi ves,

GIFimages,andJPGim ag es reducetheatta ina ble compressionproportionately).

However,theoptionalVTLPlus2.0compressionhardwareofferssignificantly

higherthroughputperformance

comparedwiththesoftware‐onlyapproach.

SpecializedASICs(application‐specificin tegr ated circuits)ontheoptional

compressioncardsperformthecalculationsthatsoftware‐onlysol utionsmust

performonthesys temCP U.

■ SupportforSunStorageTekACSLSandLibraryStationlibrary‐management

software

ACSLSandLibraryStationsupportmakesahighdegreeofintegrationp oss ib le

betweenVTLsolutionsandcomplexenterprisestorageenvironmentsthatinclude

largelibrarieswithmultiplepartitionsandmixedopensystemsandmainframe

systems.SunVTL virtuallibrariescancache

orcopytapevolumestostorage

poolsonshared,ACS LS‐managedlibraries.Al terna tively,ACSLSca n be

configuredtomanagevirtuallibraries.

■ Emailnotifications

TheVTLemailalertsfeaturemonitorsanextensiblesetofpre‐definedcritical

systemfunctionsandautomaticallynotifiesalocalsys temadministratorbyemail.

You ca n extendor modifytheCallHomemoni toring scriptstocustomi z e

monitoringforyourneeds.

■ X‐raydiagnostics

TheX‐ray featurecombinessnapshotsofthe currentstateoftheappliance,its

configuration,anditsenvir onmentwithsystemeventlogsandsavestheresultin

astandard,tape‐archive(tar)format.

KeyVTLfeaturesarediscussedinmoredetaillaterinthischapter.

Advantages of VTL tape virtualization

4 VTL User Guide • May 2008 G • 96267

AdvantagesofVTLtapevirtualization

AddingSunStorageTekVirtualTapeLibraryappliancestoanexistingtape‐based

backuparchitecturecanthusrealizethefollowingadvantages :

■ “Shorterruntimesandreduceddependency onbackupwindows”onpage 4

■ “Shorterruntimes fornon‐sequentialbackupjobs”onpage 5

■ “Improvedreliability”onpage 5

■ “Betterutilizationoftapesubsystems”onpage 5

■ “Larger, moreflexiblelibraries”onpage 6

■ “CompatibilitywithACSLS managementsoftware”onpage 6

■ “Truetapevirtualizationwithdynamicallyallocateddisk space”onpage 7.

Shorterruntimesandreduceddependencyon

backupwindows

VTLappliancescanhandleanarrowbackupwindowbyusingnumbersofvirtual

drivesoperatinginparallel,somethingthatwouldbehighlyimpractic al with

physical tapedrives.Inthisway,thecritical,fir stcopyoftheprimarydataisreliably

transferredtodisk‐basedvirtualtapeinminimumtime.Thereafter,vaulting



softwareand/or VT L tape‐cachingfeaturesca n copythebackupfromvirtualto

physical mediausinga smaller,moreeconomicalnumberofphysicaldrives.Seethe

figurebelow:

Multiple virtual drives speed backup during the critical backup window

virtual

tape

drives

virtual library

physical library

primary storage

physical

tape

drives

Back up to multiple virtual tape

drives during the critical

backup window

At other times, copy virtual tapes to

physical media using one or two

dedicated tape drives

backup

window

Advantages of VTL tape virtualization

96267 • G Chapter 1 Introduction: VTL appliances and enterprise data-protection 5

Shorterruntimesfornon‐sequentialbackupjobs

Disk‐basedVTLsystemsreduceruntimewhenstorageoperationsarepoorly

matchedtotheoperationalcharacteristicsoftape backupsystems.Properly

configured,streamingtapebackupsachievetransferratesthat areashighasor

higherthanthoseattainable bydisktechnology.Butmanycommo n jobs— suchas

incrementalsandfullbackups

ofworkstations—producesemi ‐random I/ O . Non‐

sequentialI/Okeep stapedrivesbusymounting,unmounting,andpositioning

media,greatlyreducingthroughput.Disk‐based secondarystorageismuchbetter

suitedtothese semi‐randombackupjobs.

Improvedreliability

Disk‐basedVTLsystemscansignific ant ly increasethereliabilityofthebackup

process.Backupjobsaremore lik el ytosucceedthefirsttime,becausethecritical

step—thecreationofacopyofthedata—isasimple ,fastwritetoaRAIDsubsystem.

Jammedtapes,lackofreadymedia,andoff‐line

drivesnolongerruinjobs.See the

figurebelow:

Backup is more reliable with virtual tape libraries

Betterutilizationoftapesubsystems

Disk‐basedVTLsystemscanimproveutilization,performance,andreliabilityof

tape‐storagesubsystems.Whennon‐sequentialI/Oisbackeduptodisk,tapecanbe

reservedforsequentialjobsthatcanstreamaphysicaltapedrive.Large‐scalefull

backupscan,forinstance,godirectlytotape,insuringmaxim umperformance .

Jobs

virtual

library

physical

library

primary storage

A backup to physical tape can fail when a tape

drive jams or media breaks, because a retry may

not be possible before the backup window closes.

physical

library

backup window

FAILURE!

SUCCESS!

A backup to disk-based virtual media always

succeeds, so all data is copied to secondary

media before the backup window closes.

Virtual volumes are

subsequently copied to

physical media outside

the backup window. If

problems arise, copy jobs

can be retried later.

Advantages of VTL tape virtualization

6 VTL User Guide • May 2008 G • 96267

thatproduceintermittentornon‐sequentialI/O,suchasincrementalsandbackupsof

workstatio ns, arecopiedtotapeonlyafter the yhavebeenbackeduptodiskand

incorporatedintolarge,sequentialbackupsets.Th is approachusestapedrives

continuously,atclosetotheirmaximumthroughput.Thedrivesspendless

timeidle,

sincetheymountandrepositionlessoften.Fewerdrivesandtapesareneededfora

givenworkload.Devicesandmedia suffer lesswearandtear.

Improvedutilizationofbackupmedia

Tapevirtualizationletsyoucreateemulatedtapevolumesthataremorecloselysiz ed

totheaveragesizeofyourbackupmedia.Ifyoudonotdecidetousetapecaching

(see“A u t o m a t e d TapeCaching” onpage 12),yousetthemaximumcapacityofyour

virtualtapesto 50‐60GBorto

theaveragesizeofyourbackupjobs(whicheveris

larger).Thisapproac h minimizeswastedspaceinthe criticaldiskcache,wherethe

firstcop yofeachbackupjobisstored,andmakesamaximumnumberofcartridges

availableforbackupjobsatanygiventime.Yourcopy/vaultsoftwarecanthen 

consolidatethesesmallervolumesontofull‐sizedphysicaltape cartridgesoutside

thebackupwindow.Ifyoualsoenlargethesizeofthelibrary,asdescribedbelow,

youcanaccomodatea larg ertotalnumberofthesesmallervirtualtapes.

Ifyouadopttapeca ch in g, youcannotsizevirtualtapesthisway,since,

asweshall

see,thediskandph y sic al ‐tapeimagesofthevirtualtapemustbelogicallyidentical.

Larger,moreflexiblelibraries

TheSun VTL virtuallibraryfaithfullyemulate saSunL700physical tapelibrary.

But,whiletheL700has678slots ,theSun V TL canhaveupto64000inanon‐tape

cachingsolution,dependingonthebackupapplicati o n(see“A u t o m a t e d Tape

Caching”on page 12). Thisisaparticul ar ly importantconsiderationifyou

improve

mediautilizationbyreducingthesizeofyourvirtualtapevolumes,asdescribed

above.Onelargevirtuallibrarycan,on itsown,servealltheneedsofabackup

applicationmasterserver.

CompatibilitywithACSLS managementsoftware

Tapevirtualizationletsyoucontro ldisk‐basedvirtuallibrarieswiththe same

industry‐standard,SunACSLSsoftwarethatcontrolsphysicaltape libraries.ACS LS

addsanad dit ional virtualizationlayertoyourbackupenvironment,further

reducingdisruptionstoestablishedinfrastructure an d polici eswhile,atthesame

time,bringingnewcapabili t ies.

Sun Microsystems Virtual Tape Library User manual

Related papers

Other documents