- Sun Storage Virtual Tape Library VTL User Guide
Key VTL features and options
96267 • G Chapter 1 Introduction: VTL appliances and enterprise data-protection 9
controlsNDMP agentsoftwareon thefiler(D below).Thisagentsoftwarecopies
datafromthefilerovertheSANtovirtual tapevolumes(
E)mountedbythebackup
mediaserver(
F),sonosoftwrehastobehostedontheVTLappliance.
VTLhigh‐availabilityoption
InaVTLhigh‐availabilitysystem,intelligentself‐monitoringsoftware,redundant
hardware,andhigh‐availabilityLANandSANconfigurationsprotectboththedata
pathan dyourabilitytomanagestorage.Tohelpyoutobetterunderstandthesteps
inthefailoverconfigurationproc e ss,this section providesahigh‐le veldescriptionof
thethreekeycomponentsofthehi gh‐availabilityVTLsolution:
■ “Servernodefailover”onpage 9
■ “Managementpathfailover”onpag e 10
■ “Storagepathfailover”onpa ge 11.
Servernodefailover
TheSunStorageTekVTLhighavailabilityoptionusestwose rvernodes,each
configuredtomonitor itscompanion.Eachmemberofthepai rservesastheprimary
serverforitsown storageclientsandasthesecondary,standbyse rverforthoseofits
companion.Toprotectagainstserverfailure s,eachserversends
heartbeat
informationtoitssecondaryusingaserviceIPaddress.Ifheartbeat information
indicatesa fatalerrorinacompanionserver’sprocesses,thehealthyservernoti fies
itscompa n ion thatitisassumingprimaryserverresponsibilityforbothsets of
clientsandinitiatesfailover.Iftheheartbeatinformationstopsaltogether, the
healthyserverimmediatelyinitiatesfailover.Finally,ifaprimaryse rver’sown,self‐
monitoringroutinesdetectastoragedeviceconnectivityfailureandcannot
determineifthefailureislocal,theprima ryreportsthefailuretoitscompanionvia
theheartbeatsignal.Ifthe companion,secondaryservercanaccessalldevices,
physical
tape
library
VTL appliance
NAS filer
media server
Data-mover software on NAS filer copies data over SAN to virtual tapes.
SAN fabric
Ethernet LAN
virtual
tape
library
D
E
F