You canaddanodeto aclusterfromtheAddingNodestoa clusterpanel.
Attention: Beforeaddinganodeto acluster,makesurethattheswitchzoning is configuredsuchthatthenodebeingaddedisinthesamezoneasallothernodes inthecluster.In particular,ifyouarereplacinga nodeandtheswitchiszonedby worldwideportname(WWPN)ratherthanbyswitchport,makesuretheswitchis configuredsuchthatthenodebeingaddedisinthesameVSAN/zoneasyoumust updatetheswitchconfiguration.
For availabilitypurposes,youshouldconnectthenodesinaninput/output(I/O) group todifferentUninterruptiblePower Sources(UPSs).
Before addinga nodetotheclustercheckto seeifany ofthefollowingconditions aretrue:
v TheclusterhasmorethanoneI/Ogroup.
v Thenodebeingaddedto theclusterusesphysicalnodehardware oraslot whichhaspreviously beenusedasfor anodeinthecluster.
v Thenodebeingaddedto theclusterusesphysicalnodehardware oraslot whichhaspreviously beenusedfor anodeinanotherclusterandbothclusters havevisibilitytothesamehostsandbackendstorage.
Attention: Ifanyof theseconditions aretrue,thenyoumust performthefollowing specialprocedures.Failuretoperformthespecialprocedureislikelyto resultinthe corruptionofalldata managedbythecluster.
Perform thefollowing stepsto addanodeto acluster:
1. Click WorkwithNodesfromtheportfolio.
2. Click Nodesfromtheportfolio.TheViewingNodespanelisdisplayed.
3. SelectAddaNode fromthelist andclickGo.TheAddingnodestoacluster panelisdisplayed.
4. Fromthelistof candidatenodes,selectthenumberof thenode thatyouwant to add.
5. SelecttheI/Ogroupforthenode.
Special procedureswhen addinganodetoacluster
If anyofthepreviousconditionsaretrue,thenthefollowing specialprocedures apply.Thesespecialproceduresapplywhenyou useeitherthesvctaskaddnode commandortheSANVolumeControllerConsole.Whenanodeisaddedtoa clusterthen either:
v Thenodemustbeaddedbackto thesameI/Ogroupthatit waspreviously in.
Note: TheWWNNof thenodesinthecluster canbedeterminedusingthe command: svcinfo lsnode
or,if thisinformationisnotavailable,then
v Beforethenodeisaddedbackintotheclusterallthehostsusingthecluster mustbeshutdown.Thenodemustthenbeaddedbeforethehostsare
rebooted.Or,iftheI/Ogroupinformationisnotavailableandit isinconvenientto shutdownandrebootallof thehostsusingthecluster,then
v Onallthehostsconnectedto thecluster,unconfiguretheFibreChanneladapter devicedriver,thediskdevicedriver,andtheSDDdevicedriver,before youadd thenodetothecluster.
Re-configuretheFibreChanneladapterdevicedriver,thediskdevicedriver,and theSDDdevicedriver,afteraddingthenodeintothecluster.
Note: This maynotbepossibleonalloperatingsystemsinallcircumstances.
Background
ApplicationsonhostsystemsdirectI/Ooperationsto filesystemsorlogicalvolumes which aremappedbytheoperatingsystem tovpathswhicharepseudodiskobjects supportedbytheSDDdriver.
Figure38.SANVolumeControllerConsoleNodespanel
TheSDDdrivermaintainsanassociationbetweena vpathandaSANVolume ControllerVDisk.This associationusesanidentifier(UID)whichisuniquetothe VDisk andisnever re-used.This allowstheSDDdriver tounambiguouslyassociate vpaths withVDisks.
TheSDDdevicedriveroperates withinaprotocolstackwhich alsocontainsDisk andFibreChanneldevicedriverswhich allowitto communicatewiththeSAN VolumeControllerusingtheSCSIprotocoloverFibreChannelasdefinedbythe ANSIFCSstandard.Theaddressingscheme providedbytheseSCSIandFibre channel devicedriversusesacombinationofaSCSILogical unitnumber(LUN) andtheWorldWideNamefortheFibreChannelNodeandPorts.
In theeventof errorsoccurring,errorrecoveryprocedures(ERPs) operateat various tiersintheprotocol stack.SomeoftheseERPscauseI/Otoberedriven usingthesameWWNandLUNnumbers whichwerepreviously used.
TheSDDdevicedriverdoes notchecktheassociationof theVDiskwiththeVPath oneveryI/Othatitperforms.
Perform thefollowing stepsto addnodestothecluster:
1. FromtheWelcomepanel,clickWorkwithNodesintheportfolio.
2. Click Nodesintheportfolio.TheNodespanelisdisplayed.
3. SelectAddNodefromthedropdownlistandclickGo.
Figure39.Nodespanel
4. If youarere-adding anodeto theSAN,ensurethatyouareaddingthenode to thesameI/Ogroupthatitwasremovedfrom.Failuretodothiscanresultin datacorruption.Usetheinformationthatwasrecordedwhenthenodewas originallyaddedtothecluster. Ifyoudonothave accessto thisinformation,call IBMServicetoaddthenodebackintotheclusterwithoutcorruptingthedata.If youareaddingthenodeintotheclusterforthefirsttime, recordthefollowing information:
a. Card Nodeserialnumber a. AllWWPNs
b. I/Ogroup thatcontainsthenode
This canavoida possibledatacorruptionexposureifthenodemust be removed fromandre-addedto thecluster.
Note: Thiswarning alsoisdisplayedontheSANVolumeControllerConsole panelwhenaddingthenode.
Figure40.Addnodedropdownlist
Note: EachnodeinanI/Ogroupmustbeconnectedtoa different
uninterruptiblepowersupply.Ifyoudonotsupplyaname,thecluster assignsadefaultnameto theobject.Wheneverpossibleyoushould provideameaningful nameforobjects tomakeidentifyingthatobject easierinthefuture.
Hypotheticalscenarioswherethe specialproceduresmayapply.
Thefollowingaretwohypotheticalscenarioswherethespecialproceduresmay apply:
v Fournodesof a8-nodeclusterhavebeen lostbecauseof acompletefailureofa pairofuninterruptiblepowersupplies.Inthis casethefournodesmustbeadded backinto theclusterusingthesvctaskaddnodecommandortheSANVolume ControllerConsole.
v Auserdecidestodeletefournodesfromtheclusterandaddthembackintothe clusterusingthesvctaskaddnode commandor theSANVolumeController Console.
Relatedconcepts
“Clusters”onpage11
Allconfigurationandserviceisperformedat theclusterlevel.
“Nodesandclusters”onpage11
ASANVolumeControllernode isa singleprocessingunit,which provides virtualization,cache,andcopyservicesfortheSAN.
Relatedinformation
“Scenario:typicalusagefor theSANVolumeControllerConsole”onpage 118 Thishypotheticalexampledescribesa scenariofor configuringtheSANVolume ControllerusingtheSANVolumeControllerConsole.
Figure41.AddNodetoClusterpanel
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