- Sun Storage Virtual Tape Library VTL User Guide

Key VTL features and options
12 VTL User Guide May 2008 G • 96267
AutomatedTapeCaching
TheAutomatedTapeCachingoption presentsbackupapplicationswithvirtualtape
volumesthatarephysicallyimplementedondisk,tape ,orboth.Thiskeepsthe
implementat ion simple—thebackupapplicationmanages onlythevir tual tape
volumesandvirtuallibrarie s— w hile givingthebackupadministratortheabilityto
finetunethephysicalimplementationforbest
performancean d reliability.
VTLsoftwarecanimplementvirtualtapevolumesandvirtuallibrar ies usingan
optimalcombinationofre source s:diskarrays,physicaltapes,physical libraries,and
physical tapedrives.VTLpoliciesspecifywheredatashouldreside—ondiskforfast
randomaccess,ontapeforlongertermstorage,oronboth for
maximum
redundancy—andforhowlong.Underpolicycontrol,VTLsoftwarecan
automaticallycopybackupsetsfromdisktotape,ou tside ofthebackupwindow.It
canretainthebackupsetsinthediskcacheforaspecifiedperiod,sothatuserscan
rapidlyrestoredataduringthepe riodwhenthe
needishighest.Itcanthenfreeup
thediskcachefornewbackupsetswhileretaininganimageontape.Ifarestoreis
necessa ry,apointer inthediskcachepoi ntstherequesttothephysicaltapeimage,
transparentlyandautomatically.TheAutomatedTapeCachingoptionthus
simplifiesand
automatesmanagement ofthedisk cache,insurin gadequatecapacity
withminimumdiskresources.
Policiescanbebuiltaroundthenumberofdaysthatdatasetsresideondisk,around
adiskcapacityhig hwatermark,oraroundaspecifiedeventortimeofday.Physical
tapeI/Ocanthusberun
asabackgroundprocessthatdoesnotinterferewith
productiondatacenteroperations.
Note – AutomatedTape Cac hi n g an d AutoArchive/Replicationcannotbeusedat
thesametim eonthesamevirtuallibra ry.
Virtualtapereplication
Replicatingdataprovides additionalprotectionfortheinformati on onavirtualtape
bymaintainingacopylocallyoronanotherVTLserver.VTLsoftwaresupports
threereplicationmethods,twoofthemautomaticandone amanualprocessthat can
beusedifyouarenotusingtheautomaticmethods.
Seethe
followingsubsectionsforadditionalinformation:
“A u t o Replication”onpage 13
“Replication”onpage 13
“RemoteCopy”onpage 14.