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Table Of Contents
VMware, Inc. 79
Chapter 5 Managing iSCSI Storage
Listing and Setting iSCSI Parameters with ESXCLI
YoucanretrieveandsetiSCSIparametersbyrunningoneofthefollowingcommands.
Table 56listsallsettableparameters.TheseparametersarealsodescribedintheIETFrfc3720.Youcanrun
esxcli iscsi adapter param gettodeterminewhetheraparameterissettableornot.
TheparametersinTable 56applytosoftwareiSCSIanddependenthardwareiSCSI.
YoucanusethefollowingESXCLIcommandstolistparameteroptions.
Runesxcli iscsi adapter param gettolistparameteroptionsfortheiSCSIadapter.
Runesxcli iscsi adapter discovery sendtarget param getoresxcli iscsi adapter target
portal param settoretrieveinformationaboutiSCSIparametersandwhethertheyaresettable.
Runesxcli iscsi adapter discovery sendtarget param getoresxcli iscsi adapter target
portal param settosetiSCSIparameteroptions.
Ifspecialcharactersareinthe<name>=<value>sequence,forexample,ifyouaddaspace,youmustsurround
thesequencewithdoublequotes(“<name> = <value>”).
Adapterlevel
parameters
esxcli iscsi adapter param set --adapter=<vmhba> --key=<key> --value=<value>
Targetlevel
parameters
esxcli iscsi adapter target portal param set --adapter=<vmhba> --key=<key>
--value=<value> --address=<address> --name=<iqn.name>
Discoverylevel
parameters
esxcli iscsi adapter discovery sendtarget param set --adapter=<vmhba>
--key=<key> --value=<value> --address=<address>
Table 5-5. 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.