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Table Of Contents
vSphere Command-Line Interface Concepts and Examples
80 VMware, Inc.
Returning Parameters to Default Inheritance
ThevaluesofiSCSIparametersassociatedwithadynamicdiscoveryaddressorastaticdiscoverytargetare
inheritedfromthecorrespondingsettingsoftheparent.Forthedynamicdiscoveryaddress,theparentisthe
adapter.Forthestatictarget,theparentistheadapterordiscoveryaddress.
IfyouusethevSphereWebClienttomodifyauthenticationsettings,youdeselecttheInheritfromParent
checkboxbeforeyoucanmakeachangetothediscoveryaddressordiscoverytarget.
Ifyouuseesxcli iscsi,thevalueyousetoverridestheinheritedvalue.
Inheritanceisrelevantonlyifyouwanttoreturnadynamicdiscoveryaddressorastaticdiscoverytargetto
itsinheritedvalue.Inthatcase,usethefollowingcommand,whichrequiresthe
--nameoptionforstatic
discoveryaddresses,butnotfordynamicdiscoverytargets.
Dynamictarget:esxcli iscsi adapter discovery sendtarget param set
Statictarget:esxcli iscsi adapter target portal param set
Listing and Setting iSCSI Parameters with vicfg-iscsi
YoucanlistandsetiSCSIparametersbyrunningvicfg-iscsi -W.Table 56listsallsettableparameters.
TheseparametersarealsodescribedintheIETFrfc3720.Youcanalsorunvicfg-iscsi
--parameter
--list --detailstodeterminewhetheraparameterissettableornot.
TheparametersinTable 56applytosoftwareiSCSIanddependenthardwareiSCSI.
Table 5-6. Settable iSCSI Parameters
Parameter Description
DataDigestType Increasesdataintegrity.Whendatadigestisenabled,thesystemperformsachecksumover
eachPDUsdatapartandverifiesusingtheCRC32Calgorithm.
Note:SystemsthatuseIntelNehalemprocessorsoffloadtheiSCSIdigestcalculationsfor
softwareiSCSI,thusreducingtheimpactonperformance.
ValidvaluesaredigestProhibited,
digestDiscouraged,digestPreferred,or
digestRequired.
HeaderDigest Increasesdataintegrity.Whenheaderdigestisenabled,thesystemperformsachecksumover
theheaderpartofeachiSCSIProtocolDataUnit(PDU)andverifiesusingtheCRC32C
algorithm.
MaxOutstandingR2T MaxOutstandingR2TdefinestheReadytoTransfer(R2T)PDUsthatcanbein
transitionbefore
anacknowledgementPDUisreceived.
FirstBurstLength MaximumamountofunsoliciteddataaniSCSIinitiatorcansendtothetargetduringthe
executionofasingleSCSIcommand,inbytes.
MaxBurstLength MaximumSCSIdatapayloadinaDataInorasolicitedDataOutiSCSIsequence,inbytes.
MaxRecvDataSegLen Maximumdatasegment
length,inbytes,thatcanbereceivedinaniSCSIPDU.
NoopOutInterval Timeinterval,inseconds,betweenNOPOutrequestssentfromyouriSCSIinitiatortoaniSCSI
target.TheNOPOutrequestsserveasthepingmechanismtoverifythataconnectionbetween
theiSCSIinitiatorandtheiSCSItarget
isactive.
Supportedonlyattheinitiatorlevel.
NoopOutTimeout Amountoftime,inseconds,thatcanlapsebeforeyourhostreceivesaNOPInmessage.The
messageissen tbytheiSCSItargetinresponsetotheNOPOutrequest.Whenthe
NoopTimeoutlimitisexceeded,theinitiatorterminatesthecurrentsession
andstartsanew
one.
Supportedonlyattheinitiatorlevel.
RecoveryTimeout Amountoftime,inseco nds,thatcanlapsewhileasessionrecoveryisperformed.Ifthetimeout
exceedsitslimit,theiSCSIinitiatorterminatesthesession.
DelayedAck Allowssystemstodelayacknowledgmentofreceiveddatapackets.